The practice thing can be tough if you're in a 'non dive location' - I live in Central Europe, so no sea and very few diving locations (closest is 2h) - but in order to build this ability you're looking at like... 50+ 'working on skills' dives. As an example of how much practice is good, despite having dived for like 15 years, a few years ago I entered the tech world, and quickly saw a huge difference between how I dived, and how my instructor does. In the last 2 years I have travelled to that particular lake maybe 50 times, or approximately once every two weeks on average. Sometimes for 3 dives in a day, sometimes camping for a week and diving each day. Dive-wise? V boring location. Some fish, some platforms, a car or two, 13m max depth. Training location wise? Excellent. 4e tank fills, free camping, great company. I'm now absolutely confident in buoyancy and skills for the 'real' dive trips I go on, whether ocean or Cave, because I know how well ingrained they are. The best recommendation if you don't have access to somewhere all the time is to plan a week somewhere with very cheap air fills/shore access, ignore the idea of 'fun diving' during that week, find a DM or instructor to coach you, and practice specifically over and over again the things that you want to get right. You'll be muuuuch happier for it, and will then be able to out dive most 'holiday only' divers on boats in tourist places, while looking sleek in the water