I learned how to optimize simply by building maximum level characters, initially. Reading all the rules involved for high-level characters gives a lot of info, and pouring over all the item rules and descriptions gives a great sense of them as a whole. Having a plan became more important in 3.5 than in previous editions, too, and there was more reward for being focused, mainly because the most prepared / focused characters tended greatly to outshine others.
So, my advice is to put on paper high-level characters, ask for help on the boards when you don't feel that your concept is coming together, and then learn about specific synergies and interactions. The concept is important too. When you don't understand something, definitely ask (in the least troll-like manner possible, seriously).
My first truly optimized character: a 1st edition Assasin 15 / Monk 17 dual-classed human god. Using 1st ed. Oriental Adventures got upwards of 1100 damage per round. 3.5 puts that to shame, though, but it was quite awesome to hit those numbers in 1st edition.