HELLO RVPIANO! If you haven't changed anything since changing the anit-skate, be happy! The anti skate puts a force on the arm to counter the momentum of the arm being pulled toward the spindle by the steady presure from the spiralling groove. Any serious error can put your delicate stylus into a bad position in reation to the cartridge body. The proof of this is the impprovement you heard. Stylus pressure cannot make that kind of difference unless it is HUGELY too light (you'll hear the stylus rattle in the groove) or too heavy (the arm will noticably "sag" whtn the stylun is lowered into the groove). Here's how to spot a serious alingment problem: Take a known record you expect to give you really great sound. Play the outer band. Compare this with the spound from the innermost band (track, set of grooves). Is there a serious difference? (Be sure to use a record that has inner bands that get close to the label.) How do these compare with the sound from the middle bands? If there are clear differences, then you have an alignment problem. For tracking angle checks. Find a record that sounds great: put two other records under it and listen again. Hear a big difference? Fancy stylus shapes can be very fussy here. Conical styli cartridges are not very fussy at all. If you hear a big difference (you should), which is better? If the elevated record sounds better, you have an vertical angle tracking problem. Nothing will blow up if you fiddle with various adjustments. Often tracking at the highest recommended force will cure a lot of problems. Be sure the little connectors on the pins of the cartridge are very snug. Everything should be clean and shiny.
If your hands shake a bit (as many do), leave it to the pros (or a really sharp kid from the record shop)! Happy listening!