Thank you ALL very much for your advice!!
It's seems that the first step it's to step up my portfolio size and then worry about income and different agencies. 

My small portfolio is basically of different trips I've done with my girlfriend. I tried a couple of objects but didn't sell well.
Any tips to find a nich o different subjects to produce from home? I've started a home studio based on another project to make product photography at the same time so I've got some tools.

Hello everybody!
First of all I take the opportunity to introduce myself.
I'm Diego from Argentina, Buenos Aires.

I've been following this forum for a while now. It has been super useful  from resources to personal opinions about the business. It really gives me an idea of what to expect.
I understand that this will not be my main source of income but I'm crazy about photography and enjoy selling my photos.

I'm really a newbie with only 200pics portfolio and the first main issue I'm having is that in SS the sales are going great and as I expected with good growth when uploading but this agency on it's own is not enough. I read several times that it should represent more or less 50% of my income and the other 50% the combinations of other agencies.

Right now I'm uploading to this agencies and this are the results for June 2014:

- Shutterstock $44 (Usually $35-40)
- Dreamstime $3.5
- Istock $12
- Fotolia (First uploads then stopped) $0
- Canstock $0
- Bigstock $2.25
- 123RF $4.37

As you can see:
Total $66.12
SS 66.54%
Other Agencies 33.45%

I'm doing something wrong?
Should I take other approach to other agencies?
In order to keep growing my income which is the minimum percent I should increase my portfolio per month?

Any suggestions are more than welcome.
Thanks in advance!!