First time I played I've been on Korriban first, then Dantooine, Nar Shaddaa and Onderon and personnaly I think that order sucks since you got all your party member by the end of the game and that let you little time to get influence with them.
Now it's my fourth time and I do:
-Nar Shaddaa. The part with Mira in the Jekk Jekk tarr is pretty easy since I put all her skill in stealth (and pick the stealth cross class feat when I can) and keep a free stealth generator in my inventory so all I have to do is kill Hanharr and stealth pass the gards. I also keep a few skills for security since you can't bash doors in stealth.
-Dantooine. There I find the crystals I need for the lightsaber I made on Nar Shaddaa and find Disciple.
-Onderon. Find Mandalore.
-Korriban. This planet is really short and by that time of the game the PC should have enought XP to go throught all the things quite easily.
Hope that helps!
