I am the King of bad choices when it comes to leveling a character. If there's a mistake to make, I've made or am about too. Respec recipes cost a million or so in the auction house, so make mistakes. I decided that my lvl 37 corrupter needed Medicine, bought a respec and tried it out for a couple lvls and when it wasn't working out by 40 used an earned respec to lose it. 60 million is more influence than all my characters have so any mistake you make is easily fixable.
Decide what you want to be good at, single target or crowd control, long drawn out fight or over in a blink, or solo or group play. Attack it with a plan and vengeance, if it works out, great, if not maybe ditch the plan and try again.
I can't offer technical expertise as after reaching 50 I unlocked and slotted Judgement, Interface, and Alpha in that order on my main. I used to 5 or 6 slot the powers I used the most and take my chances on the rest. Now I slot 1 every 10 levels if it is important and use any leftovers on what isn't important.