I find that I'm very much not an optimist at all, actually. I find that looking forward to things in a positive light generally leads to the grand anti-climactic disappointment at the end.
On the other end of the stick, I find cynicism to be just as counter-productive, since I find it difficult to get myself up and moving to do anything if I look at it all with a negative end in sight.
I approach things with a realistic end in sight. I consider the most probable outcomes, and if I have control over the result, aim for the one that would please me the most. If I don't have control, I prepare for them all, having escape plans from the negative ones at the ready. I'll often spend a lot of time and energy thinking all this through, too. Or even finding scenarios, both likely and unlikely, then finding their possible outcomes. (this usually ends up being worst case, too. I like to be prepared...) I find that this way, I'm occasionally surprised and in a better mood at the end of the day than I expect, and very rarely let down. It also makes surprises that much sweeter (but the disappointments that much worse, because I can only think "Why couldn't you do it? It was an absolutely realistic request, and you screwed it up.").
If that even makes sense.