I think one thing that may help that I haven't seen mentioned yet, is to read the codebase you are working on (not all of it, unless it's smaller than a novel)
Pick a certain starting point and follow it down the rabbit hole. Rinse and repeat.
A couple things I find helpful about this practice is: one, it let's you compare the over all architecture against the true implementation (which can vary), and two, it gets you comfortable with the implied standards--the things that can't/don't get written on a style guide (e.g. they keep prepared statements in a separate, common file)
Pick a certain starting point and follow it down the rabbit hole. Rinse and repeat.
A couple things I find helpful about this practice is: one, it let's you compare the over all architecture against the true implementation (which can vary), and two, it gets you comfortable with the implied standards--the things that can't/don't get written on a style guide (e.g. they keep prepared statements in a separate, common file)