"If you could give me just one tip for getting better sound from my turntable rig, what would it be?"
We've heard this question at Tenacious Sound more than once, and it's an excellent question. There are many acceptable answers--ensuring that your cartridge is perfectly aligned and set at the right tracking force is one good tip, and placing your turntable on a solid surface that reduces vibrations is another.
But the single best tip we can offer vinyl newbies is this: make sure your turntable is level!
You can usually check this out with an inexpensive level, especially a bull's-eye level or spirit level. Place it on the platter and see how level the playing surface really is. If it's off, you can usually fix it easily via the adjustable feet on your turntable. (Most modern turntables have this feature.) In a worst-case scenario, you might have to adjust the furniture underneath the turntable. But it's still a relatively easy fix.
Having a turntable that is not level will cause it to sound horrible. A lateral tilt can wreak havoc on the anti-skating, causing your cartridge to lean on one side of the groove more than the other. (That will usually result in distortion or additional surface noise in one channel.) The stylus on your cartridge will start to wear unevenly, as will your LPs! Even the main bearing on your turntable prefers to be level at all times.
Worst of all, your records will just sound terrible. So take a few minutes and ensure that your analog is perfectly level. Your rig and your LPs will thank you.