The tips and ideas in this post are mostly aimed at microstock photographers / image creators, and for the most part are ideas for promoting work, your profile(s)/website(s) and selling more images...
1] Only upload to the top sites,
You might want to upload to some of the up and coming microstock sites to evaluate your earnings, but in general it will take a lot of your valuable time which you can use more better elsewhere. But always keep your uploaded images ready for submission to other sites as the market changes will will find yourself wanting to upload them again elsewhere.