Tracking and Scheduling
You'll come to realize over time as projects become larger and more complex, that in order to save your sanity you're going to have to start getting organized so you can properly track what you've finished, and what's left to be done.
Because you'll be working on the lighting in areas that are going to most likely be altered over time by Environment Artists and Designers, things can get confusing. It's pretty rare that you'll be able to start on the first level in a game, work your way through bit by bit, finish it, and then move on to the next level. The same holds true if you're primarily lighting cinematics rather than the game levels themselves.
Until you reach the end of the project, things are in a constant state of flux.
You worked on the warehouse level last week. Did you set up the probe volume yet for the characters? You lit that cinematic with the ghosts and the old woman...did you set the vignettes for that scene yet? How about the depth of field? The fog?
Unless you have a photographic memory or a mind like a steel trap (I have neither) you're going to need a way to track these things so you'll know what's still in progress (and what state it's at) and what's been completed.
Everybody's got their favorite tracking software, and it may be that you'll end up at a company that already has a system in place. If there is no system in place, it would be a good idea to set up something for yourself that you find easy to use and easy to update.
Note that I'm not talking about bug tracking software like Jira, I'm just talking about an easy to use method of note-taking.
I've used Microsoft OneNote, Excel, and other programs over the years. If you're just setting something up for your own use, you should be able to use whatever you're comfortable with.
Here are a couple of examples of systems that I've used:
Keeping a sheet like this up to date for each level will keep you from going crazy. As quickly.
The above sample shows a system that can work well for a "player path" type game, with a flow through a series of levels with a starting and ending point. For an open world game, you'll probably be dealing with regions or areas rather than specific paths, so something like this might work better:
These are just samples, but you get the idea. Feel free to make whatever helps you keep on top of things.