How to get back into Wicca,without doing long,frustrating rituals/ excersizes and doing it all over again ?

Hun, any religion, teaching, heck hobby asks for practice, patience, and persistence. You do however have a one up on a newbie. You already have practiced so all you have to do is get back in the groove. For visualization I would try simple first i.e. you see a sweater try to "see" it in a different color and than hold that image for as long as possible, than move on to bigger things. As for your abilities, meditation really does help, it helps you to clear you mind and focus on one single object. The more you are able to control your mind the more you will be able to control your abilities.