69 position is always good - then you can get pleasure too! 69 is a good position because you can easily alter and shift eachother to the comfortable level.
Having her on the bed while your on your knees will help too. Use some pillows for her to sit on if your need to get the height right.
If she is lying on the bed and you are between her legs, you could try having her propped up on pillows to raise her up a bit.
You could try her on top if she is comfortable with it and do the awful-named 'facesitting', while your head is rested on pillows and she could alter her movements to help you gain access.
Otherwise, just keep changing position periodically so you aren't in the same position for ages which will cause unnessicary neck/shoulder ache.
Hope that helps. x