Strattera can take up to 8 weeks to reach it's full strength. Sucks, I know. But once it's built up, it does work... :P

Anyway, yep, I have the same problem with starting tasks. What helps me is making the thing interesting. It helps get you motivated. For instance, if I'm trying to work on a homework assignment that's boring, I might write it in glittery pen and in fancy cursive (instead of normal printing). Or if I have to type it, I might choose a fun font and a fun color (and then just format it after I'm done typing it).