Tips for deepthroating

Please help out with some tips for deepthroating! My boyfriend says I give amazing blowjobs, but I know he loves being deepthroated and I just can't go *super* far. I feel like I could go farther, but every time I try my tongue ends up getting in the way and I gag. Is there any way to get past this? I'd love to be able to give him everything he wants.