First off, I must clarify some things: Neither do I hate guitarists or believe they should somehow "serve" the bassist. Music is a mutual conversation that should always be balanced. With that having been said, I find that in more times than not, there is a musician (in my experience usually a guitarist) who completely becomes absorbed in his OWN playing. I will discuss ways of NOT doing this when playing with a good, balanced, bassist. (Yes, we are assuming the bassist is ALREADY good to simplify things)
1) Watch And Listen: This means be aware of what the other players are doing. You have to be flexible to common occurrences like calling a key change or someone making a mistake. Or maybe someone (your good bassist or good drummer) decides to "change up" a groove. You should follow this. Remember, it's about the band as a whole, NOT just you. The good bassist and drummer will complement you when you change up a groove as well.
2) Match Volume: Ever notice how, when you're in a car with only the bass bumping, you can still pretty much hear yourselves talk? That's because higher frequencies carry better. Low frequencies may have more energy, but high frequencies are more "hear-able." Ever notice how, in a 100 piece marching band there is a ROW of Tubas and only one or two piccolos? Next time you play, if you can't hear every note the bass player is playing, you are too loud.
3) Turn Down Your Lows: Sorry, but cranking a guitar amp's low EQ does NOTHING but muddy a mix. It should NEVER EVER be done unless you are playing by yourself. Here's the rundown: Your guitar D string is about 146.8 Htz. When you EQ for good mixes, the bass should occupy everything beneath 200 or so (with the exception of the kick). That means that the lower strings on your guitar are USELESS unless you keep the bottom off of them. This is one of the most prevalent mistakes I hear guitarists make. The bass is the bass. Those frequencies under 200 are his not yours. A good bassist respects your soloing. Respect his frequencies.
4) Play Your Own Part: I'm not talking about doubling the bass line for Spanish Castle Magic or Crossfire. Those are static bass lines that don't change much. What I am talking about is when you are playing a line (especially boogies) and you decide to try to lead the bass on a walk. Sorry, bro. Unless the line is done the same EVERY TIME, that is an instant fail. And I hear guitarists play the most awful choices for walking bass lines too - ones that will chromatically interfere with the bass line just because they want to somehow "add" to the good bassist's part. Great rule of thumb: DON'T DO IT unless the part never changes. Just make room for each other.
5) Don't End The Song By Yourself - unless the song is done that way: I hate "K-CHUNK" on the end of tunes because a guitarist believes he needs to be the last one heard. And the bad part is I have heard guitarists who have done that SO MUCH they aren't even aware they do it! End it with the band.
6) Use Signs: This one goes back to the communication issue. But good bands will watch each other and ACKNOWLEDGE when a member calls a change. It's just common respect. It doesn't HAVE to be the singer or guitarist who gives a change either. Using hand signs gets rid of confusion and makes your music better.
7) Lay Out When You Need To: If you think music is "boring" just because your part calls for silence, you shouldn't be playing music. A good bass player will lay out in the verses of "Alright Now" and a good guitarist will lay out until almost the end in the song "Some Kind of Wonderful." Just listen to Warren Haynes for some great "when to and when not to play" guitar work.
8) Cut Out The Attitude: Yeah, we know you can play 1200 notes per second and make Steve Vai look like a 4 year old playing Guitar Hero. But that doesn't mean you are god. The more people you respect, the more you'll be respected. Why do you think some "lesser" guitarists get more gigs?
9) Play With Control: That's right. Don't let the odd string ring out while soloing or playing. WAY too many guitarists do this. It's annoying and non-musical. DON'T DO IT! Learn to play in Eb or Ab or Bb and keep practicing until no strings ring out uncontrolled. Just do it.
10) Know Your Accompaniment: In other words, if you play a song, play it correctly. Or let's say the bassist takes a solo, don't play louder than him or just strum chords behind. LISTEN to some great bass solos and (for the most part) lay out. This all ties in with making room for each other and respect as well as knowing your role musically.
*The list is not meant to sound condescending. If anything, I hope you find a little humor in the tone I use.*
Thanks for reading.