"If it comes down to a field sprint, you probably won't win, so don't let it." - shovelhd
So either work on sprinting, especially the jump, or try everything and anything to separate yourself from the field before the sprint. You won't be able to just ride everyone off your wheel. Try attacking from the middle/back of the pack, using a course feature to separate yourself, attacking immediately before a break gets caught, etc. This is what racing is all about, learning how to use your comparative advantages.