I've never had a fuel problem doing bomber escorts, but I also enjoy the challenge of flying a mission where my biggest enemy is myself (the plane I'm flying, how I fly it and especialy how much fuel I burn while doing it all) followed by the guys trying to shoot my bombers.
First, as a fighter, you can safely take off 10-15 minutes after the bombers have, or much later from a closer airfield and then rondevou with them. This isn't hard but it does typicaly take more coordination than you'll find on the MA (bombers take off a A1, escort takes off at A11 at T+20, escort waits for bombers to arrive at A22, everyone heads to target A33 after the rondevou).
The main thing though as a fighter is to get above the bombers and then cut back your fuel consumption to often less than maximum cruise. You want to match the bombers speed as closely as you can (communication between the escorts and the bombers for matching speeds and headings makes this a lot easier). Not only do you save fuel by burning it at a much lower rate, but you save time/distance by not having to waste fuel for circling around the bombers (as you fly ahead of them when going faster). When enemy contacts show up, throttle up and drop down to the bomber's alt as needed.
Something I've recently experienced with most of my sorties in the BoB '08 scenario (flying 109s, we had maybe one sortie where we weren't escorting JU88s or JU87s), the thing that struck me the most this scenario wasn't that we were burnning so little fuel while escorting (just matching our escort's speed and heading, 5k above them as they cruised and climbed to target), but that we would burn up so much fuel when we weren't cruising above our buffs and had to engage the enemy. WEP or no WEP, more than 10 -15 minutes at full throttle and I would have to calculate breaking formation early for fuel while escorting the bombers back home (ontop of whatever fuel I would need to rejoin and catch-up with the formation flying ahead to it's target, since our combat engagements with the RAF rarely if never continued to follow our escort (and often this was a much larger waste of fuel than the brief combat engagements we had to chase the RAF away from our bombers)).