Oral 101 Helpppp

I can suck dick fine without gagging. I want to deep throat but for some reason I can’t without gagging and I cant go all the way. I used to gag just having it in my mouth but now when it goes a little further I gag and can’t take it anymore. His dick is like 6 inches and I hear about people deepthroating like 8 all the time. How can I suck dick more easily without gagging and how can I do it better and make my man feel better?