Some hotkey uses will make you a tremendously better player.
T (obvious quick return to main base or expantion bases, for whatever you need).
Control groups for military are a MUST. Develop standard groups and always use the same ones, so it becomes second nature. So you don't have to think about it at all. It will become pure reflex after a couple of weeks. This also helps for when forces are off-screen. You don't need to waste time scrolling, finding them. Press the control group and get 'em to where they are supposed to be.
For example, for me heavy infantry is always (1). Light infantry is (2). Artillery is always 3. "Specialist" forces (Culverins, Grenadiers, Spies) are always (4). Melee cavalry is always (5). Ranged cavalry is always (6).
Explorer is always (8). Very early game any scout unit such as an Envoy is (9), but is usually replaced (see below) when I hit Colonial or soon after.
Control groups for military production buildings are almost a must. If you have to move the screen back to your Barracks every time you want to train something, you'll miss alot of the battle action, which will results in worse performance in them. You can't effectively micro forces if you're not looking at 'em.
For me, for example, Barracks are always (7). Artillery Foundary is always (9). When no specialist troops are used, Saloon is always (4). When no ranged cavalry is used (think Colonial conflicts), Stables are always (6).
Using these hotkeys WILL make you a better player. However everything else is largely superfluous. So I don't use any other ones.
"One wants to be loved, failing that admired, failing that feared, failing that hated and despised. One wants to instill in other people some form of emotion. The soul shudders before emptiness and wants contact, no matter the cost."