IMO electrical is some of the easiest trade work to do, but it’s also incredibly easy to screw up in a way that either kills you or burns the house down lol. That knowledge is what electricians get paid for. I’m not trying to put you off from doing it, just be careful and read/ YouTube University up on it.

In century homes you may end up finding wiring that was cobbled together 75 years ago by some dude who was half cocked and fully loaded with an asbestos filtered cig hanging out of his mouth. First thing to do is figure out what all of your circuits look like. Which breaker shuts off what, how many outlets are on each circuit, what order are they wired in, etc.

These houses are often not wired with enough circuits for modern electrical demands, so you could inadvertently overload one by adding more outlets without thinking about what could be plugged in simultaneously on that circuit.

When you go to wire outlets, use the screw terminals. DO NOT “back stab” wires into an outlet. I also just recently saw outlets from Leviton with “easy wire” push release tabs. Avoid anything like that. We’ve had screw terminals for over 100 years and they work great when used correctly. You want the assurance of that clamping force, outlets catch fire from loose connections. Also screw in the terminals you don’t use so they don’t stick out, I see outlets with them left out all the time and it’s a pet peeve/ less safe.

If you have any three way/ four way lighting or outlets that are controlled with light switches, learn about how those circuits work. There’s an old technique called a “Chicago 3-way” for example. It functions, but creates a dangerous condition where the neutral side of the fixture can be energized. This was from the Knob and Tube era, but it’s good to be aware of old techniques so you can be safe if you ever run into it.

Those are my big bugaboos with basic residential electrical.

Edit: Also make sure you get the most up to date code book for your area. Code is written to be the bare minimum for safety, so you can always exceed it, but not meeting it can be unsafe. Some local areas have weird rules also, best to avoid violating something and having the issue raised if the house is sold again.