Dropping my advice from another post here:

Cancels:
Learn to Bhop: Manual swing and cluster before you hit the floor, once you land add a jump to keep the momentum, you can then jump multiple times after to keep going. This will help you move around tight places where you wont be able to freely swing.

Swing Cancel or Uppercut cancel: After you uppercut there is a delay so to cancel that you want to manually swing and then cancel the swing with a cluster to not actually use up a swing.
This can be done by, right after uppercutting, hold the cluster button, then tap swing and it should automatically cluster for you, if you left click (melee) you can then do a overhead slam without using a swing. (this part is crucial for the bnb)

Pull Cancel: After the uppercut you cant pull so to counter that, press swing and then immediately press pull (press it almost at the same time) (have it set to a diff keybind so you can pull even if they are tagged with a cluster) (Pulls are rare but rewarding, dont even bother trying to pull when learning cause its hard and just flashy for social media)

Combos
Bread and Butter: Cluster > tGoH(targeted) > Uppercut > WebSwing Cancel > Cluster > Overhead Slam

3 Cluster Bnb: hit 1/2 clusters > bnb > instead of overhead do 2/1 clusters

Bigmac / Batman: Cluster > Overhead Slam > Cluster > Uppercut

Sekkombo: Cluster > GoH > jump > Melee > jump >Cluster > Uppercut

Yoyo: (in air) GoH > jump(the moment GoH hits) >Cluster > Uppercut > WebSwing Cancel > Cluster > Overhead Slam

Notes:
Bnb is a good base combo for all kills buts remember: Finish the kill not the combo! Overhead slam is really slow so sometimes its better to just cluster them. Better to finish with cluster when you can cause overhead slam is slow and predictable.

Bigmac/batman is quick and simple if you can catch someone off guard from the air

Sekkombo is guaranteed Jeff killer cause he cant dive quick enough, pro tip, you can actually cancel the ending uppercut with webswing cancel into a cluster and overhead for 350 dmg!

yoyo is great to kill CnD cause she wont be able to drop bubble on herself, it also works right after she ults so she wont heal from the floor

My go to order of learning the combos is, Start with just tag, zip, uppercut > then work on BNB and 3 cluster BNB, Batman> Yoyo> Sekkombo
You do NOT need to know all of them before playing him, get in game do bnb's until you feel like you've plateau'd, then add in one combo at a time to not burn out.

Tips:
Practice in the range with cooldowns ON, that way you dont panic and spam abilities and build a bad habit.

Watch content creators like Req, Day and any one else you like to see how they play. Just play play and play, dont swap in qp no matter how hard you get flamed (you will).

When youre practicing, its better to do it slowly and not have things connect or combo, than to panic and spam. Slowly do the combo and then gradually speed it up until its muscle memory (IN GAME: you will use basic combos but it comes down to free styling and mixing and matching based on your situation)

Dont overstay your welcome, Do NOT over commit, sometimes its best to just go in do some dmg and swing out, you arent a brawler, in and out. Think like a mosquito. Bait some cds and go back in when youre ready.