The first thing you should know: take your GRE about 1 ½ to 2 months before your earliest important deadline. It is going to take approximately that much time for your score reports to reach the universities you have chosen as score recipients (i.e. the universities you chose to send your score reports to). Here’s what the ETS says:
For students who have given the GRE several times, the worry has always been that the universities they are sending the scores to will see their bad scores along with their good ones. Now, however that is going to change.
The ETS has introduced a feature which it calls the ScoreSelectSM Option which allows you to select which GRE scores you want to send to the universities and colleges you are applying to. Here are the details according to ETS :