If you ever feel like changing which apps load whenever you boot up your Mac, you can go to System Preferences > Users & Groups > Login Items, then add, check, and uncheck whatever you want to prioritize.
Whenever you need an accent mark (or related foreign character), just hold down the appropriate letter, and a list of relevant options will pop up.
We've all had those moments where there's a certain word you want to write, but can't quite remember what it is. If you know you're close, though, just hit Fn + F5 as you're typing something, and you'll get a list of similar words right then and there.
See a word you're not familiar with? If you highlight it and hit Command + Control + D, you can get dictionary definitions and Wikipedia info without having to leave your page.