One of my favourite tricks that I use when cooking lamb to get all of the flavour inside of the meat, is poking holes in the lamb and stuffing about 1/4 of a clove of garlic inside. Before putting the garlic in the lamb, I coat it in salt, pepper, and oregano. This makes sure that the garlic flavor goes throughout the whole lamb, and this is especially useful when cooking bigger chunks of meat such as the leg.