Only answer to that is to upload furiously on a constant basis I suppose.  But I think that might take some of the pleasure out of what we do.

Hatman, this is what I do.  I began uploading small batches on a regular basis. The day the pix are posted, I  experience higher sales.  BUT, it isn't just the newly posted pix. I will sell pix that could be months old as well.  For the next couple days, the sales decrease.  Then I upload another small batch and do it all over again.  I haven't had a zero sales day at SS since early January. 
     I don't know if it is a coincidence or what, but in the last two months, my acceptance has been in the 90 percentile.  I'm also getting less than 24 hour approval.
      I would say this. If you are one that experiences high sales the days your pix are posted..... try uploading smaller batches more often and see if a pattern develops. 
    For the last 3 months, I can't say anything bad about SS. It's the only site bringing me mad money.      -tom

MODIFY:  In a couple of other threads, I'd been throwing around an approximate number that impressed me about SS. That was what percentage of my portfolio was being sold. I did the math.  SS has sold over 77% of my portfolio. Now, I've never seen that number discussed so.....
      I have no idea if this is good or not. Basically I have the same porfolio everywhere give or take a couple dozen pix. Some sites have sold less than 10% in the same or longer time.
          I'd like to throw that question out to you all.  Which site sells more of your total portfolio than others? And what kind of percentage of the total are they selling?

I started with SS 02-19-2007 and 15 days after i made $29 with 50 images on line. Plus, on SS almost all my images sell and on IS i have one hit with 85 dls and the others hardly ever sell.
I owe IS the quality of my images, i learned a LOT there and still learning, they are relly helpfull on the forums... but SS wins when it comes to $$$, i get to shot what i want and it sells... so... learning to love SS 

I just applied to IS last weekend... have heard nothing yet and based on what I've read here, I'm not holding out a lot of hope for being let into the club.   
   I can echo latex feelings. I have to say that the bulk (now upwards of 80-some %)  of my portfolio on SS  SELLS. No other site sells even 30% of my 'folio. Why?  No clue, but I'm not complaing about it. 
   As far as the continual upload theory?  Yeah, I think you do have to upload on a regular basis to SS.  So I adopted a strategy some time ago of uploading small and I mean small batches 2 or 3 times a week. I am then getting a regular acceptance and posting of new shots. I have seen the pattern consistently. The day a new batch is posted, not only do I sell them but even shots months old sell too. I guess the buyers take the time to browse my old stuff.  At any rate I see a dramatic increase in sales... then sales decrease over the next couple days until the new batch is posted. I'm not spending any more time in the upload process as I would uploading 50 in one shot, I'm just doing less more often, but it keeps the $$$ coming my way. 
    If I get into IS, who knows how it will go?  Personally, for me now, IS has some big shoes to fill to match my sales at SS. Yeah, it's only 25 cents a pop, but I'm selling a whole boat-load of those 25 centers.  For the last few months SS has accounted for 80+% of my total sales.  -tom

Okay, here's my story.   Uploaded a batch of 27 on Feb 6th.  Evidently 25 were approved somehow during the migration [according to email sent to me last week].  They didn't show up in my portfolio until today.  Today is the first time I've been able to access everything on the site.
    Problem: I have pictures showing downloads, but no evidence of the download in my account.  I'm waiting a few more days for them to finish working out the bugs.  If the money isn't in my account by monday, I'll be ringing the phone off the hook.    -tom

My 25 approved images from February 6th,  still aren't in my portfolio...  march sales as seen by the downloads on the pictures still aren't in my account.    ?  this migration sure isn't going very well.....  I'm starting to rethink 123 myself.  I'm only going to hang on a little while longer, I may bail out..............    -tom

on reviewing...
personally, i think all reviewers should be designers, the folk that actually buy the images, they would know best what is needed and what is usable.
 

Great point, Void!!    -tom

Wow, is that true?  4 cents a pop???  That explains why they have 'bad days'.
     I think that if I owned or managed a micro agency, the reviewers would be some of my best paid 'salaried' and fulltime   employees.  I would think that these folks are the frontline bread & butter of your success. Your business would only be as good as what they approved or turned down.  They should be highlly trained in the standards that you expect the customer to find in your agency's portfolio.
     'Peice work" mentality in reviewing photos I think would be counter-productive.  At the same time,  I would expect that these well-paid reviewers would be aggressive in their review process.
      But then that's only my humble opinion.  Afterall, I know jack-squat about what goes on behind the scenes there.
    -tom

Great news, wooohoooo.
I got accepted 7 out of 10 were OK, the other three had noise.
Happy happy happy:)

ALRIGHT!!!!  CONGRATS!!    -tom

Presumably it will also 'die' if I stop uploading, as many people here have pointed out.

hatman -    My sales at SS are consistent everyday.  Due to comments like the above by others more experienced than I here on MSG, I've gotten into the habit of uploading a small batch of pix every couple days.  I don't know if that helps, but....          the sales are there.  Also, the sales are NOT only those new pix. I'll sell stuff that was uploaded months ago along with the 'just uploaded'.  I don't know how the SS system works, but...    at this time, I'm not complaining.    -tom

Phildate couldn't have put it any better! Great advice!
    I am amazed how many of my pix that were rejected for one or more reasons  (focal point not where we think it should be, not stock material, too many on site, not looking for this, blown highlights, soft focus...even noise... and more) 
    ...are on those very sites that rejected them and more, are selling on those sites.  Do not give up.  Believe in your work.
     On the other hand, sometimes they are right. Some of my pix were exactly as they said and needed more work or needed to be trashed.
      Believe in your work but don't throw humility to the wind. It doesn't hurt to look at the rejected photo from their perspective. But.... if they're wrong,  they're wrong. Keep submitting!    -tom

I've been declind the 3rd time already on Shutterstock and I'm getting desperate. All my decent selling images can't get accepted at SS.

Cheers

Canakris -- Don't get too upset about a 3rd rejection from SS. That seems to be the SS way. Most of us were rejected by them 1,2,3 times or more. I was rejected 2 or 3 times. ..with some of my best stock pictures...
   However,  I finally got on.  AND.... in time, most of those pix that were initially rejected..I later resubmitted and are now on SS and selling very well.  Go figure!?!
   The point about noise is valid. SS is fanatical about noise. However you may find that many of those can be cleaned up and will be accepted on a resubmit.  Also, you do understand that when your batch of 10 is rejected, not ALL of the photos are necessarily rejected?    -tom

here's my humble collection at LO

thanks!

Gotcha covered, Khwi.   Did one of your paragliding shots.  I REALLY did enjoy them!!    -tom

It might seem contra-intuitive to ask you guys whether I should go out and increase competition for you but I'll do it anyway ...............................
................A lot of people here say its there best performer in terms of $ but the $0.25 per dld has so far kept me from going there.  So, what do you think - is it worth my while uploading and categorizing all over again?

Tina

Tina -   By all means,go for SS.  SS is a top earner!!   I'm on 9 sites and SS is my #1 consistently.  In the last  3 months, SS has brought me over 80% of my sales.  Yes even at 25 cents, how?  VOLUME!!  Just pure quantity of sales.  You'll find your top images selling multiple times per day.
      SS can be a tough one to get on.  They are fanatical about NOISE. As far as subject, speaking for myself, I have everything from animals to isolated inantimate, but mostly landscape/travel.  They all sell.  Someone made a comment about them being picky, but what the pick, SELLS. That's 100% correct!    In my case, I am nearing the 90% mark of my portfolio having been SOLD.

As far as the competition thing goes....   ...well, first off, welcome to the gang here at MSG... that being said, I think you'll find that the folks here are like a family.  Since I've been here I have never seen any hint of a competition mentality. Rather just the opposite. When you have questions, or need advice, there is no shortage of help to be offered. And, it's generally great help. I personally have learn a lot about the business here in this forum.      -tom

WHOA!!!!!!!!!!!!!!!     I SHALL COMPLAIN NO MORE!!!    Man-o-man.... Freezingpictures, that IS a record!!    Hang in there......  or.... something...    I think I'll try that  forum angle!!   WOW....    -tom

modify:  well, I just got back from the 123 forum. Left a query about my pix.   5:09 pm est,  3/2.     we'll see what develops. 

To quote Arnold Schwarzenegger in one of his movies ...  "I LIED"...
To quote me,  "I shall complain again."   I finally got back on 123rf today only to find my 27 uploads from February 6th,  are   "missing".. I'm wating on reply from support....       I sure hope it's my stupidity in that I just haven't been able to navigate around the new site....  but I'm pretty sure it isn't me...           we'll see.      -tom