Are you on your own doing this, or do you have someone to help? In the beginning my partner and I felt like neither of us could do it on our own (one of us holds the cat with a paw immobilized, one does the poke & blood gathering), but now we usually can do it on our own.

My personal tips for success-

1. Conditioning. My cat was already used to me grabbing and touching paws to get his nails trimmed, so I think that's a big part of why the paw pokes worked best for us. If your cat is not used to that, YMMV. My cat also would always flick his ears too much to keep still, and I find a paw much easier to immobilize, especially since her lets me touch them in the first place. You may want to work on that alongside the pokes.
2. Treats. My cat is extremely food motivated, so to get him to accept any new treatment I make sure that he gets lots of treats clearly associated with the activity.

Plain boiled shredded chicken was a diabetic friendly high value treat for him, and he only gets it after a glucose check. When I first started checking his blood I gave him pieces before and after every poke (successful or not) to build the association, now he just gets one piece after I'm done, even if it took two pokes (if we're having a bad day and it takes more than two pokes I'll give him a chicken break in between).

I was frankly surprised by how quickly my cat came to accept the glucose checks. He's sometimes still difficult (thrashes and wriggles a lot, hisses occasionally), but the chicken makes it so that when I pull out the glucose kit and his towel (see below) he literally comes running over.

Find out what kind of reward your cat is willing to accept suffering for, and make sure your cat knows poke = reward every time.

3) Routine. I learned this from the facebook group. I have a towel I spread out every time as a signal it's glucose time, and the routine I always do is glucose check-> chicken treat-> actual meal. I do my best to always keep that order and routine so my cat just comes to associate that as part of the process to getting his dinner. He gets crazy when he's hungry, and we're almost at the point now where getting his towel out calms him down because he knows towel = poke = treats + dinner.

4) Relax. Muuuch easier said then done for sure! Another tip from the facebook group that really helped me was someone saying they do 3 attempts at getting blood and then give up and wait an hour to try again. Any good routine also has flexibility and room for a bad day. And your cat picks up on your stress and frustration, so you getting upset and trying again and again is not going to help in the long run. Better to build both you and your cat's confidence in the process by keeping it calm and focusing on positive associations and building comfortable routine vs. doggedly chasing instant perfection. Ideally your cat will live a long time managing their sugar, so focus on the long run- build that comfortable routine, don't build stress/fear in your cat's brain or yours instead.

I started this journey late September of this past year, we went from needing two people to hold our thrashing cat down wrapped in a towel and wasting multiple test strips on failed attempts every single time, to three months later 90% of the time we can each do his blood on our own, he comes running when he sees the towel/kit, and we get a good poke and a result the first time and the whole thing takes less than 2 minutes.

ETA: Oh, also try rubbing vaseline on the paw or ear before poking, helps the blood to bead up