If I am bullsih on the project I may never sell but if I know a project is nly a pump and dump I just enter for a quick flip and never look back, For icos my strategy is to get my intitial investment early and hold the rest for next pump
Selling at a very good price anytime of the day is also my strategy but that's only for alt coins that has a low concept and less community support. For those potential altcoins, i am really holding it for good no matter how high its price may get.