You first need to be able to do 1 rep at the new weight
So what I did was, I would add weight, then aim to get to my 5 reps. If I get to 4 reps, I will count the last rep as a failed rep, and try the same weight next session/week depending on program. If I fail that 5th rep more than 2 weeks is when I go for a deload, which is typically going back 2 weeks in a linear program.
Thing is, the smaller weight plates will just help to deload less, especially if you are in a bad stage when you deloaded more than 2 times.
Eating more usually helps, but I personally don't find it helping me all the time, but I have seen it help others. Usually though, I am at the worst end of genetics, so I just find it much harder than most, not blaming it, but I pretty much use every trick in the book to keep on progressing.