Playing bass is plain and simple, just play the music from the heart, feel the piece and let the listeners enjoy the melody. Here are a few basic tips that could help beginners.
Make a decision about the bass sound to be played. Will it be like a real smooth bass player or just a machine going wild over the sound? It will depend on the rhythm you want to use.
It's not against the rule to do some personal experiments. Move the track forwards or backwards to see which sounds better. A 2 or 3 millisecond in increments can be used in audio. When the bass is ahead, the drums can sound far behind but if the bass is left behind, the drums may sound "burning".
Shorter notes sound better than the long ones if a bass part of the audio is "pitched". Edit some notes taken from other parts of the song to fit them into a totally different phrase. The melody is still familiar but with a different cut because it was inserted on a different line.
Leave some space in the bass part of the song. Notice that famous bass players put emphasis on holes when they try to emphasize a feeling of pressure into the sound. It leaves the listener's ear hanging in anticipation and then satisfying them just a few beats later.
Avoid making bass melodies that can cause difficulties when playing and playing will not be as enjoyable. Some parts of the bass can be very attention grabbing especially if the rhythm is extremely fast. The trick is keeping the frets static until the melody changes. Like playing drums, bass can be recurring as well, so manage to break lines and chords for some variety. It is not bad to go back to the first simple bass chords just to avoid having a "wreck" with the sound at the end.
The inspiration for playing to suit the bass chords depends on the way the song is played. Sounds with more bass melodies are best heard when the notes are kept higher. Never hesitate to edit notes so that they are comfortable to play. The best advice is to listen to the edited bass chords and be decisive on the good and/or the bad timing. Remember that too much of a good thing can turn out badly, the same with playing bass, when exaggerated, it could ruin the whole piece. A little highlighting on the initial beat of a song's phrase can do the trick. Enjoy playing!