How to calculate base-emitter current
The base-emitter junction will drop around 0.7v when fully "on", so...

3.3v - 0.7v = 2.6v to drop

Ib = 8mA (the amount of current you desire into the base)

E = I*R

R = E/I

R = 2.6v / 8mA

R = 325 Ohms

325 Ohms (330 standard value) will give around 8mA into the base, at 3.3v and with 0.7v being lost from base to emitter.