Remember the estimated fuel burn the default FS flight planner gives you is wrong. I've found the figure given is approximately 130% the fuel burned by one engine. My formula for fuel planning is (( FS estimated fuel burn x 0.75) x 4 ) + total / estimated trip time.

That usually gives me enough fuel for taxi and then a missed approach and a TOGA or two :D

For longer trips I multiply cruise time (usually trip time - 1 hour) by fuel burn rate at chosen FL, for more precise and optimised fuel planning.

As for fuel distribution, I follow the procedure as detailed in the manual to the letter. Hasn't failed me so far.

Cheers

Nico