Use your hands, be enthusiastic (sounds, dirty talk,etc), look them in the eye, touch and caress them, move not only your mouth but your head, swivel side to side, be relentless in your pursuit! Dont switch up what you are doing too quickly before it has an effect. If you get tired, use ur hand or hands (the two hand technique is a favorite ) during the break so that you arent back to square one when you go back to using your mouth. Oh and don't watch porn for tips, they give the worst BJs
just lots of practice is the best teacher.
I'm a swallower... but if your aren't, just move your head out of the way at the last minute but keep using your hand and the uh male juices to finish him completely off, he will usually be asleep within minutes after this so make sure you got yours first