tips on how to get a better 1/4 time

[MADED-6]

well i went to calder park on friday night and my best time was 15.41 at 92.28mph (i thought it was a little higher but i was wrong) i was hoping my car could run mid-low 14's
now i think it still could because on that run my times were
60ft - 2.446
660ft - 9.995 at 73.12mph
ET - 15.410 at 92.28mph
no on that run i got a fair bit of spin in 1st and 2nd gear and i am not a very fast shifter and never flat shift or anything.
i got told to flat shift 3rd to 4th and go really hard from 2nd to 3rd i dont do this beacuse i dont think i am quick enough.
i thought i was going to get a 14 but missed third because i got 1 2.2 60ft time but as i said i missed third in a bad way and thought i stuffed my gearbox.
now i am going to the aff drag day next month at heathcote and would like to get some good times there.

my car consist of a fully rebuilt bottom end with slightly higher comp acl race pistons (9.2:1) and then headwork done by swanny (trick_xd) and a dev5 cam and just paccie 4499's and 2.5inch exhaust. it is manual with a b&m short shifter and it has 3.7 diff gears. i was running 205/65r15's on the night at 27psi then i tried 20psi and still couldnt get grip. now as i said my 60ft times are getting better but still need alot of work as i am getting spin should i let th clutch out slower or wat. i am frustrated as i just spent $4,000 rebuilding the motor and it feels alot better than it used to and gives alot of cars a run for there money. i can beat my brother in his au3 xr8 by a little bit and i smoke ba's and the sort.
sorry for having such a long thread hopefully someone can help me out.
cheers josh.