The most important thing with recording guitar is the sound you’re making in the room. You have to start there, and that will often come down to volume. If you’re going to a recording session, it’s good to have a few amps there of different wattage. Anything can work but if you want to make a good guitar recording you need to be aware of the acoustic environment you’re in.
Attack is very important and that can often be about what kind of pick is being used. Pay attention to the way a pick hits the string, because it can be many things – aggressive, non-aggressive etc. Someone can be playing super light and ask, ‘Why doesn’t it sound aggressive enough?’ A lot of the time these things are in the playing. I mean, you could have a kid pounding out a riff on a classical guitar into a mic on the other side of the room and it’ll sound more aggressive!
Learn to use reverb like a pro. There can be so much reverb slowly added in that you don’t notice it creeping up on you because your ears get used to it, then suddenly it’s just really confusing. Sometimes you EQ the shit out of long reverbs, especially if you’ve got a lot of them in a track. In fact, I like to take all the bottom off and only let the upper-mids through. It’s great because you get the effect of a giant reverb, but it doesn’t muddy up the mix.
Choose your weapons carefully. Sometimes a ribbon mic can be great on a guitar cab, but you can’t have the amp absolutely bollocking if you’ve got an old ribbon mic next to it because you’ll just trash it. So maybe back off the volume a bit. They’re very fragile. You can stick an SM57 straight on a Marshall that’s going full tilt and they’re OK, but with a ribbon you can't do that – it’ll burst.
Finally, noisy power adaptors can be a problem. When you’re playing live, people don’t notice it as much, but as soon as you put a mic in front of an amp, all of that noise is immediately heightened. I tend to take everything out of the signal chain that’s not being used and only include what we’re actually going to be using. That way you’ll be working with as clean a signal as possible.