What is the most Effective way to learn?

i hear that repetition is the best way of learning,but personally i learn quite slower than others. I have always seemed to be the one who turns their work in last in the clroom,always the one who gets called on for the right answer and sits and hesitates to think of the correct answer, and always the one who has a hard time making fast decisions that are accurate.My memory is not up to the point where i would like it to be either.I can barely remember last week. Also i have noticed that i do things in different ways than others,like i write my "4's and "7's" different from the majority of people that i know....and if there were an easy way to do something,i usually don't notice it right away. Now i know I'm not an idiot, because i have had honors cles in the past and past them with fairly decent grades,i just learn at a much slower pace than others for some reason.WHAT COULD THIS BE? maybe a change in my diet could help me be more quick minded? What factors should i look at?