One piece of advice I give to guitarists looking to improve their sound is to turn up their amplifiers and play louder.
It's for a few reasons.
First, if you play in a loud and aggressive form of music, like hard rock, metal, and punk, then louder volumes are definitely your friend.
Second, your technique changes when dealing with a loud amp, where any small movement can cause an explosion of sound. This forces you to reevaluate and reassess your technique, specifically your left and right hand muting techniques so that people only hear the notes you want them to hear, and no sympathetic vibrations from the other strings.
Third, there's a funny thing with amplifiers and master volumes. See, you'd expect the master volume to work like your car's stereo volume, where it just gets louder and louder in a linear fashion the more you crank up the volume.
But amplifier volumes don't necessarily behave this way, and depending on the amp, you can run into a situation where turning up the master volume won't actually make the amplifier louder.
Not only that, but depending on the amp, it may actually change its amplifier class, where it operates in Class A over much of the range of the master volume, and at the last bits, it starts operating in Class AB. This makes sense, as you get the best tone over the majority of the sweep of the master volume, and then the amplifier gives you the extra volume when you actually need it.
And not only that, depending on the type of amp, it may actually sound better and distort more the louder it is.
And finally, if you don't practice like this and don't have the experience of how your amp behaves at louder volumes, when it comes time for it to actually deliver, like in a band or recording situation, you will find out the hard way, very quickly how that amp behaves. Suppose you're in a band, and you're being drowned out. If you have an amp that's chucking out the most volume it can, and you need more volume, then turning up the master volume doesn't make the amp louder, then you have found out exactly the use case for that amp.
A lot of bedroom musicians are simply unaware of these variables, and don't realize that a lot of their gear is only appropriate for bedroom practice, and not serious gigging or recording.
Typically, when you warn them of this, they take it to mean that their rig is garbage. No. It's just not appropriate outside of playing by yourself in a bedroom.
So seriously, turn up the volume on your amps. Find out how it sounds and behaves at higher volumes. Also, get used to playing with loud amps to the point that any small movement will create noise. This will improve not only your sound, but your technique too.