When I log, I log before/during cooking of the meal. I'll usually plan my meal on myfitnesspal so I know what all to make so that it fits my macros.

And for eyeballing after making the same things over and over and weighing them out, you start to get a feel for how much it is you need. Every once and awhile I'll weigh out what I eyeballed to make sure I'm not going too low or high.