If you tell us more about your present dive experience, we can help you better...
There are several paths you can follow to become more proficient with buoyancy. The first and most obvious one is to do more dives. The more you dive and the more natural buoyancy will feel. Start with easy dive sites with not too much water movement and work your way up from there. Remember to stay calm and that most of the job for staying neutrally buoyant is done with the lungs, not the BCD. Also, make sure you are properly weighted. It is a bad idea to carry too much weight since this will force you to rely on your BCD for buoyancy.
There are also courses that you can do. The PADI Peak Performance Buoyancy Specialty specialises on buoyancy. It is a 2 dives course and can be done over one day. If you're just PADI Open Water, you may want to consider taking the Advanced course. 5 dives under a good instructor's supervision should enable you to master this most important skill.
There are a lot of places where you could stay to dive in Bali.
Sanur is a bit far from dive sites, but has many restaurants and hotels available. The party and surfing down in Kuta is not too distant.
Tulamben is popular with hardcore divers. There may not be much to do beside diving.
Padang Bai is still a traditional Balinese village despite some infrastructure in place to cater for tourism. Good diving can be done just a few minutes from your hotel.
Candidasa offers more options for hotels. Dive centres operating their own boats often have them moored in Padang Bai.
The diving on Bali is often described as being far superior than that of the so-called Gili islands. Bali's underwater scenery is renowned for its diversity.
