One of the most effective things you can do to optimize body composition is improve insulin sensitivity. If you're more insulin sensitive, it'll be easier to build muscle and lose fat.
Insulin is a storage/anabolic hormone. Anabolic means "to add." It's released mostly in response to an increase in blood sugar. We could say that insulin is triggered by the need to lower blood glucose back down to normal levels, and it does so by favoring the entry of glucose (and other nutrients) into the "storage facilities" like muscle cells, fat cells, the liver, and brain.
As such, if you're more insulin sensitive, you won't need to produce as much insulin in response to an increase in blood sugar levels, and if you're resistant any increase in blood glucose can really jack up insulin release.
This is important because the more of a hormone you produce or release, the longer it'll take for that hormone to go back down to baseline levels.
Insulin being a storage hormone directly increases storage of nutrients into the various reserves, including fat cells. So if insulin is high and there's a lot of fat present at the same time, you'll increase fat storage.
The other part of the equation is that elevated insulin reduces fat mobilization. As long as insulin stays elevated, you'll be inefficient at losing fat. If you're more sensitive to insulin, you don't need to produce as much to get the job done, which means it doesn't stay high for as long and you can spend more time being in a fat loss state.
One simple thing to do to optimize insulin sensitivity is to take apple cider vinegar and omega-3 fatty acids about 15-20 minutes before your meals. You don't need much. A tablespoon of vinegar and half a dose of Flameout® prior to any meal containing carbs is all you need.
If you want your body to do an even better job at improving insulin sensitivity, take Indigo-3G® in the morning. This supplement significantly and rapidly increases insulin sensitivity. And even more interesting, it improves insulin sensitivity selectively in muscle cells, meaning that your body will more easily store nutrients in the muscles rather than fat tissue.