first and foremost, learn to keep yourself sheltered. if you can't navigate yourself frm the back of pack to the front without having to side-blast in 20 minutes or so, you know where you need to work (credit @
MDcatV)
this assures that you don't burn as many matches
next is to do less work and stop pulling people around. Attack with determination (25-30 seconds full bore). Look back after 40 seconds or so. Do you have a sizeable gap? If not, sit up and wait for a better opportunity to attack (credit @
shovelhd). those oppurtunities would be on hills, in crosswinds, after a corner, and/or during lulls in a race. on a windy course, attack on the crosswind section right before a turn into tailwind. The crosswind allows you to gutter and establish the gap, the corner allows you to extend the gap a bit, and tailwind allows you to maintain advantage even if the pack is chasing.
also keep in mind the strong riders in your field and mark them.
lastly you may be over-estimating your FTP (although this is mostly a moot point for the issue here). How is that your 20 min power is lower than both your LT and FTP? If you can't do 20 min at 290W, then your FTP surely ain't 290W.