to chase or not to chase, that is my question

edit: sorry about the title... i'll leave that for the next question, lol
This one should be "help me tighten my game please"

So I've been applying alot of my studies to my game, and I can see my bb/100 are coming out of the negative. Bottomline hasn't changed much, but I'm not losing nearly as much as I was overall.

But there are a few things in my game I need some help with if anyone is willing to take the time.

First major one is barreling:

I know this is very opponent related and there is no one correct answer for all situations
But doing ev calculations at the table while multi-table playing is not an easy task for me yet. As far as my hand reading skills, they are improving but also have a ways to go.
I can usually tell when a fish is going to fold after a flop that missed me and I cbet since I raised PF. I understand when I raise pre from the button with say J9o and two limpers in early position call me but the flop comes 52Q and it gets checked to me this a good spot for a cbet and 99% of the time I'm taking down the pot.

But it's the times where a board comes dry like this and one opponent calls the cbet after checking and the turn comes say A. So there's 52QA and one limper who called my PFR and my cbet but checks back to me again. My feeling here is usually if I KNOW this opponent very rarely is going to limp an A and then call a missed flop with only Ax and now checks when an A does hit what is the proper bet amount or action here?

Normally I would bet about half pot here and I'd say 50% of the time opponent will fold and the other times he will call. On the river there is another blank card like an 8
At this point when opponent checks, what is the play? I feel like I almost never bet here and usually check behind at which point I muck my hand and hope no one was watching as I lose to a pair of deuces or if they were they keep this in mind next time I have a monster against them

So mainly I have done a ton of reading and practicing and I feel like my preflop game has improved immensely, but at times I find myself not knowing what to do on the turn and on the river.

I'll leave it at this for now and have another question later...

Thank for any insight, or even a link to maybe some reading material that goes in depth with these kind of hands.