One of the most difficult elements of playing bass is improving your finger strength. Stronger fingers will improve your accuracy and help you to avoid hitting any bum notes, particularly with your little finger. Naturally it is used a lot less than your other fingers so the pinky needs a proper workout to get and stay in tip top shape.
For bassists, tone is literally in your hands. You can go from a dull thud to a sharp, funky punch simply by choosing where along the string you pick it and how aggressively you hit it. Your best weapons are your hands, so take good care of them!
Play with people
When you’re playing in a group you're connecting with other musicians, each with their own experiences and skill sets. Who knows what tips and tricks you might pick up? By playing with a range of players you’ll improve your own abilities. A great bassist can play everything, but the perfect bassist knows the appropriate time to play everything, and that only comes with experience.