Pulloffs?

Unless you're using the hammerons and pullofs for a different effect, it can be a bad habbit to get into rather than just plucking the note.

 

Slurs - hammerons and pulloffs - are really not a major part of bass playing, but if you use them you really have to get them down. *Nothing* sounds more lame than badly executed slurs on a bass, with the possible exceptions of badly executed slurs on a guitar, or out of tune fretless bass. Wuurgh.

Oh yeah, slurs. Hammering is easy, just mash the offending string with a finger of your choice. Just like being a drummer, right? When you pull off, your pulling finger pulls at the string a little to keep it ringing clearly. For practice, start by fretting the F on the G string with your 1 and the G with your 3.

Now, the slur - with the 3 finger put a little sideways pressure on the string while keeping your finger in place, and then flick the finger sideways off the string in the direction you've applied that pressure. Most people choose to pull down (groundward), but that's arbitrary - choose whichever is more comfortable. The F which your 1 is holding down should ring out nice and clear. If you've pulled too hard it'll sound crap. If you haven't pulled hard enough, the note won't be clear and as loud as your normal notes. If you do a lot of slur practice your fingers might start to hurt - don't worry too much about that.

Ideally you want to be able to slur just as loudly and effectively as normal playing, on any string with any combination of fingers and/or open strings. That's a lot of practice. What you want even more is to avoid cramming slurs into a song just because you can - it makes you sound like an amatuer.

Oh yeah, and practice practice practice. But that goes without saying.