Why do you particularly want to focus on raising GH levels? Are they low?
It is critical to understand that GH is counter-regulatory to insulin. It therefore causes an elevation in insulin needs that is equivalent to a mild degree of insulin resistance. Insulin itself blocks GH, so If you go to sleep, or train with high insulin levels, you block secretion of GH. So insulin resistance is a main cause of low GH, and adding GH can make you more insulin resistant in the short term.
GH can be blocked by metabolic insulin resistance or by chronically high cortisol/adrenaline levels.
In the long term, good GH levels will block chronic high cortisol which will raise insulin sensitivity, and promote a positive cycle of healthy GH secretion. The point I am making is that if you are trying to raise GH levels directly, but you have chronically high cortisol levels, and or developing insulin resistance, it only makes sense to try to fix those issues first since GH acutely raises insulin needs.