I agree with  hitrawal91 , read about technical indicators or check out some of the stuff on technical trading for forex or equities...you dont have to know it all to get a good idea when to enter or exit...

Generally you need to know how to look at the order book and gauge the support levels .... Also trying to get out at the top and in at the bottom all the time is impossible no one ever knows the top or the bottom. The idea is to earn money consistently  try to set a target to earn on each trade and don't be to greedy...if you make 5-7% per intraday trade your doing great ..