Just practice daily. you and I share a similar background; I also took Judo and Jiu-Jitsu, Karate as well. Aikido is so completely different frome these (already very different) Martial Arts, you're going to find you'll have to 'unlearn' a few skills to develop your Aikido.
So, don't worry about memorizing the techniques; your body will learn them just by practicing. Just relax, enjoy, have fun and listen to your instructor - you'll find yourself snapping off a halfway-descent kokyunage or kaitenage(one of my faves) in no time.
Cheers! And welcome to Aikido, by the way!