This is a bit stream of consciousness and so it's not organized at all but I think you'll love reading it anyway.
Most important rule of a blowjob is Wetness wetness wetness.
Ok?
Wetness is very important.
Watch some videos online and see all the available different techniques.
There's hundreds of them.
They all work.
Everyone's different so don't worry about which techniques may or may not work. Try as many as you like in each session you are intimate.
Here are some favorites:
With cock in mouth getting sucked up and down or keeping cock bottomed out in your throat, do this - both hands are scratching balls and scrotum and below (taint), in the middle and on both sides - this feels AWESOME!!
Just make sure area is nice and super wet. You can lick it or spit on it or apply it to your hand and then to the area. Spit lube cream lotion oil, whatever you have, remember there is no wrong lubricant and there is no wrong way.
Some guys want your fingertip or a knuckle or the whole finger or a toy in their butt and some don't. It's a very sensitive area so definitely explore and check reactions. Both you and he may be pleasantly surprised.
Caress thighs and the whole general area or run fingernails on the skin - oooh shiver :-)
Scratch balls all around especially on the sides at the seams where legs meet.
All up and down the sides and then the front of the sack.
They may even like it when you pinch some scrotum skin and pull it outwards a little bit and / or just rub it between your fingertips a little roughly or twist it.
Then tiny little bites all over the scrotum to make him feel fantastic.
All around the anus with licks sucking-kisses nibbles is oh so damn good.
If he's amenable, some gentle prostate massage is usually welcome. Some guys want it hard and fast.
Give them what's they want.
So yeah, the whole damn area from asshole to perineum to scrotum to balls to base of cock to shaft to head/frenulum should be wet and stroked scratched kissed licked nibbled on bitten chewed upon sucked pulled pushed twisted pinched slurped and be snacked upon.
There should be some moaning on your side too so they can tell you are enjoying doing this for them.
You making the right noises drives men wild and many times makes the whole session last a lot less longer.
Use your throat - take it in till his cockhead hits your throat and use your throat to squeeze that head and just contract around it if you can.
Alternatively do short strokes making the head hit your throat as that may make him cum.
When sucking, sometimes go all the way down and all the way up instead of just doing short sucks halfway or just sucking the head.
It's great.
Sometime with full strokes, once he is all the way in, stay down there for a bit feeling his full cock in your mouth.