help me pick him out!

[fcbarrelracer]

i am planning on picking out a new betta, i the next week, from our lfs or a petsmart or or petco so..
i want to get a younger one if possible (so he'll be around longer)
a unique or pretty color
pretty fins
healthy
a good personality
etc.
how can i tell all of these? how can i pick out the "perfect" (or as close to ) betta?

thanks