You should PRACTICE learning the names of notes on the fretboard and developing your technique. PRACTICE diatonic and chromatic scales and arpeggios to develop your fretting hand. PRACTICE alternating your index and middle fingers when you play. This develops your playing hand and builds speed. Try to play along with songs you like. When you hear a bass player on a CD do something you like, try to copy it note for note. This develops your musical vocabulary. Just like babies can learn a whole language by copying what they hear, you can learn the language of music this way.
Here's a tip for becoming a good choir musician. If you get a good handle on hymns and congregational tunes, you'll have a solid foundation for playing choir tunes.
Above all PRACTICE PRACTICE PRACTICE DAY AND NIGHT!!!