Basically there are three issues that affect buoyancy control. First and foremost is weight and weight distribution. Second is trim, good horizontal profile. The last is buoyancy or vertical movement in the water column. Work on these in the order listed. This will simplify your efforts. I agree that an experienced professional is your best option, unless you have experienced dive buddies that were past professionals.
Weight: At the end of a dive, with less than 500psi in the tank, at 15-20ft of depth, remove all gas in bladder and normal or 50% lung capacity. Next, remove weight until you can no longer hold the depth. Then add one pound back. You will likely be able to remove that pound or more in the future. As you progress with experience your "normal" lung capacity will change allowing more weight reduction. However, don't make this a challenge, weight needed is what it is once you find it.
Trim: This is where another set of experienced eyes pays dividends. You need video or eyes to tell you your profile. Move weights up or down to balance your profile. I had to do both, at depth I needed weight forward to level off trim. However, at the safety stop I was finding myself head down. So, I moved some up onto cam bands and added a weight belt. The weight belt did not move it far, but it was enough to balance the safety stop.
Buoyancy: This will now be much easier to manage. The key that I found was to set my BC gas at depth and only change it when my lungs could not compensate. This is generally more than 10fsw of change. Work on managing depth changes with volume in your lungs. You will learn that you can change your lung volume quite a bit and still maintain slow steady breathing. The hardest part is waiting for the change because it will not be quick, be patient. The more air you have in the BC to compensate for wetsuit compression or gas the longer it will take for change to occur. Once you get a feel for this delay you will learn to start the change a bit earlier. I used PVC rings to learn the timing, over and under.
The first two can be done in a dive or two, the last one takes some time to master. Keep working on it and you will find the comfort zone fairly quickly. Keep diving and keep enjoying your time underwater!
