There is a way that one can play Skyrim and defeat most enemies with relative ease by pretty much just being a cheapskate. You can defeat anything from Elder Dragons to Dragon Priests. The technique doesn't work when battling Karstaag or the Ebony Warrior, but it's pretty efficient the rest of the time. You don't even need to use the technique all the time- make any build you want, and if you discover a foe that's too strong for you, just use this technique.
Here's how to set it up:
1. Obtain the Sanguine Rose or any other staff/spell capable of summoning a Dremora or atronarch. Staffs are better for this technique.
2. Equip some other kind of ranged, one-handed attack such as a spell or staff in one hand, and your summoning staff in the other.
3. Hoard all of the Soul Gems you can, you'll need them to charge any staffs you use. Additionally, you should hold on to any and all summoning scrolls and spells you can find.
Using the technique:
1. Summon your Dremora or atronarch.
2. Hide from the more powerful enemy while mopping up any smaller foes/minions in the area.
3. Repeatedly throw the Dremora/atronarch at your enemy. Any and all enemies, even bosses like Miraak, will focus on your summoned creature before attacking you, but ONLY if you do not approach melee range.
4. Staying at a distance will keep the enemy at bay while you hit them with your other spell/staff. Utilize spells, shouts, or powers that can aid your allies from a distance.
Alternatively you could just take Windshear off the Katariah and be a total douche, but what's the fun in that?