A classic technique for thickening parts is to “double track” them, meaning to record the same part again on another track. But that doesn’t necessarily mean that the subsequent doubled recording should sound identical to the first track. Try varying the sound of the doubled track. One way is to use an alternate instrument, so if you have multiple guitars, for example, try doubling by using different guitars — record the first track with a humbucker-quipped guitar and the second using a single-coil guitar. If you don’t have different instruments, if you are doubling an electric guitar part, try using a different pickup position — bridge for the first track, neck for the double. Or, if you have access to different amplifiers use them. Only have one amp? Change up the gain and/or tone controls for the double. Use a different microphone to record the double. Add an effect on the double. Play in a different register or use chord inversions…there are tons of things you can do to change up the sound of the double, which will make your parts sound even thicker and help create a dense “wall of sound.”