I don't really use it for leveling, so I generally start throwing powers I know I'll take in there, and fill it out from there. Then I'll usually have a general goal in mind as I start. For example, I'm about to work on making an Elec Melee/Shield Scrapper, so close to perma-hasten and soft capped defenses will be high on my list. I'll start slotting my primary and secondary powers with specific sets to help me get more recharge and positional defense. For my first run I'll actually go through it pretty quick and not looking too deep at it. Then I'll check out my first draft end usage, recovery, defense, and recharge and tweak from there. For this specific build I'll be going for positional defense, so if I notice my fire defense is 30% I'll look at the sets that give that and see if they can be swapped out for something that gives more Ranged defense or recharge. A friend and I that played together for years have a shared Google Drive folder and we'll look at each other's builds a lot, so that helps give fresh eyes and someone to bounce ideas off of.
I realize my method isn't the most organized so it may not work for you, but I find it effective.