So I haven't been playing bass for very long, but since I started playing I've always had a problem with sliding. I'm currently learning Uncle Salty by Aerosmith, and at the beginning of each bar in the verses, there's a slide on the E string from the 12th fret. My problem is that it always sounds messy or incomplete and I can't figure out what I'm doing wrong. Any tips on improving?
Well; without seeing or hearing what you are doing, it is difficult to analyze your technique. Smoothness is one of the keys to a good slide. If you are rushing it, it generally sounds too loud at the beginning and cuts out too quickly. You are basically playing all of the notes between those two frets as one; they should sound even and ring out a the same volume. That is a bit more difficult with the bass, as the strings are thicker and you are amplifying bass frequencies instead of guitar frequencies. Try practicing just slides up and down the fretboard. Strive for smoothness and accuracy. Oh; and if you are using some major cheese-grater strings like Dean Markley's Skullbusters, you are going to have to switch strings. Those really sharp-wound stainless steel roundwound strings are just too damned noisy for smooth string slides. It will always sound like a ripsaw.

A lot of slide problems (usually going up the neck) have to do with bad accuracy. The easiest way to fix this is just before you make the slide, you look at the fret to which you are sliding. It will immediately and dramatically increase your slide accuracy, and it works for descending slides, too. Try it and see if it helps.
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