So I have been manually curating for a long time on Hive but I haven't had much luck on curation rewards.
I have tried manual and different curation trails but my curation APR was always low... pretty much garbage. I pretty much gave up on curation and I was okay with it since nothing was working.
You can check your stats here.
https://hivestats.io/
The other day, 
https://hive.vote/dash.php?i=1&trail=josevas217
I was't doing well anyway so why not. I had nothing to lose and joined the trail. About a week or so after I joined the trail, nohting happend.
My curation was still garbage. I wasn't expecting anything anyway...🙄🙄🙄
But then few days ago, it started to pick up, and now I am at 9.5% and I am getting few HP just following the trail.
It is still early but I think it is working maybe?
Here is my setting on https://hive.vote/
Upvote threshold is set to 80% and if it goes lower than 80%, it stop voting until it gets charged back to 80% or more.
And my Voting weight is set to 100% Fixed so it is always voting 100% not scaling.
And then the wait time is set to 5 minutes. Default is set to 0, but I think if you vote within 5 minutes after a post is up, you won't receive any curation HP... or something.
I normally wait like 30 minutes, but it seems like that is not the best either?
So this is my setting and hopefully it will get better and better! We will see.
If you know better settings, please let me know ;p