The algorithm for Best Match is a closely guarded secret and constantly changes, sometimes huge changes.
At this moment,'Best Match seems to have a large weighting on 'new'. For a long time, 'new' files were totally buried in the best match.

Various factors can apply to different degrees - sales, views, age, exclusive/indie, keywords, random, etc.
Sometimes indies are favoured in the best match, sometimes exclusives. Over the past year, the same algorithm doesn't seem to apply to all searches.
Semi-right keywords can actually negate your main keywords, but again, it depends on which algorithm is in use at any given time.

I haven't looked up the image you are talking about, but guessing (and I could be wrong) that your image is 'isolated on white', 'white' isn't a good keyword. However, you can have 'isolated on white', and 'white background', also isolated (as you had) and 'plain background'.

You don't need 50 keywords for most images. Sometimes I struggle to think of five, other than the generics, e.g. colour, photograph, horizontal, nobody (etc) which possibly no-one searches on. Usually I have between 10 and 25 including generics. Very occasionally I've got to 50 and had to cut generics, but really very seldom.

You're not cursed, it's not personal - though it certainly can feel like it.
Many people are reporting the same thing this month.
Over halfway through the month and I'm at 1/10th the $$ I got last Jan, and have only 6 dls.
Remember, they made a concerted effort to change their credit buyers to be sub buyers, (after making a previous concerted effort to turn their credit buyers in to Thinkstock buyers) AND credit buyers can easily choose to filter out all our your non-essential files when searching.
It's worth investigating whether your genre/s might do better elsewhere.
I know mine wouldn't but plenty of indies report better overall totals after leaving exclusivity, though others don't.
Of course, independence takes much more time to upload to many agencies and keep tabs of what goes where. But balancing that might be the sense of freedom and lack of dependence on one outlet and their random whims.
It all depends on your port and your personal circumstances.
Plus you have to decide what you personally are prepared to put up with in terms of the cr*p all of the agencies throw at us.

To begin with your keywords and descriptions are terrible.
Your descriptions aren't descriptive enough and I looks like you average 7 keywords (the few shots I looked at), not enough.

Quote from: muratttix on January 18, 2015, 12:18

Hello guys,
First of all i follow what you all wrote in the forum, thank you all for your help.
2011 August i started work for stock photography and come long way.But my sales was low both sites and i decided to join Istock exclusive program,i've 1500 image but just 1 download last 20 days. I'm starting to believe that the damned  If problems related to me ,what do i need ?
I read that forum posts sales falling for everybody,i just worried about have I got a wrong decision by become exclusive.
Thank you

You have been since 2011 so you know all the issues with being exclusive with iStock.  Going to iStock as 'Exclusive' is like someone going back to the Titanic after the ship is more than third quarters under water. Why on earth would you do this?  You better hope you're a very good swimmer