trilling probs...

i have a trilling prob...when doing a 2 string trill, i do this:

B--18-15----18-15----ect
G--------17-------17-ect

when i should do this

B--15-18-15----15-18-15----
G-----------17----------17-

how do i fix it its the first note the 15th tht i miss, i usually just pick the 18th pull to the 15th the pick the 17th i should pick the 15th hammer 18th pull 15th and pick 17th...im trying to fix but its hard...any suggestions?

by hard i mean like instead of playing the first 15th as a 16th note i play it as an eighth or even a quater.

Pick the first 15, then H/P then Hammer on from nowhere on the 17.

ill try tht but its mainly the 2nd time, i seem to like pause to hit the first 15th.