You know all those (0/5) perks? Leave them at 1. Anything more is overkill. Craft all you want using your skills. Meaning, don't use fortify blacksmith gear or potions to improve your weapons and armor. Use your skill only. Same with alchemy and enchanting. With that only, you have a very challenging game on expert.

Play on Master / Legendary, take off the HUD, Don't wear any armor (or just any good armor), and just use a decent weapon.

At least that's how I make so I'm not Over-powered.

I still went the route of putting up Smithing and Enchanting, I just limited myself from making something a bit too cheap.

I've been doing all at once.

Yes. Yes, this does make you overpowered. However, I haven't overdone them yet, so I'm not that awesome. (yet)