Anything above the average stats of your current rank are good. That means you're improving. Thing is, the average hook accuracy for both gold and gm players is the same because the enemies move differently across different ranks. Gm players are harder to hook, and thus only gm players can play against them. Same for gold. So just aim for stats above the average for your current rank. Also, with hog, the utility you give to your team matters a lot. He's an amazing shield breaker and that really doesn't show on your stats. But if you consistently break enemy shields, it means you've done your job as well. With your hooks, it's also about target priority. If you hook a reaper who fades away, it'll still count as a successful hook but it is useless. So you need to work on hooking the right targets. Dvas are always a good idea if you can demech them. Time your hooks with your team's engages so your team can help finish off kills quicker. Hooking healers is worth it. And it's extremely valuable if you hook down enemies from high ground positions. And as Pharah/Tracer, the worst thing for me is a hog that's good with hooks and keeps oneshotting me.
As for self healing, you can use it to make the enemy focus you so your team can engage better. But you need to make sure you're not just feeding damage to their ults. Your job is to deny space, not be a meat shield.
