This is such a nice question, and so will it be so very helpful to so many .
there are a number of things I look for from a broker and the best to actually know and think of is
1. the speed in executions, you dont want a lagging trade in entry or exit, believe me that can be really bad for you
2. the fees, let it be easy on you to break even , there is a difference between a broker who has a spread of 5 say on GbpUsd , whole that one who has 0.4 will be positive 4.6 in profit before the other one gets his earning
3. Methods of deposits and withdrawal should be perfect and very friendly to everyone.
4. advantages given even in bonuses ,
5. Safetly of funds