For anyone looking at this post on Xbox, here's how I leveled up when I played, though it takes a long time. In total, I'm showing how to upgrade Restoration, Alteration, Block, Speech, Smithing, Illusion, Lock Picking and Sneak.
Before reading, know that the only way to level up is by leveling up your skills.
Restoration — Definitely not the fastest way to level up, but it works. Especially if you have a follower. I noticed simple healing magic didn't normally level me up, by jumping off a high surface and healing over and over etc. — So what I did was heal other people when they were downed. This is slow but it does work. You can get it up a little bit during the block section.
Alteration — Got me about 4 levels in an hour just by using the Telekinesis spell on random objects. Once your magika runs out, just click the wait button and repeat. Also check smithing.
Block — Easiest way to level up in my opinion. Equip a good shield in one hand, and a heal spell in the other. Go to Markarth (far top left on the map) and kill one guard inside the city. Now leave the city and immediately go left or right, pushing through all the guards who teleport outside. While going up the steps, you'll see a hole going toward outside. (You cannot leave through the hole!) Go in there, crouch and hold the block button. There will be lots of guards. This worked great for me and it took around 40 minutes to get from block 57–100.
Speech — For this one, make sure the Khajiit are in Dawnstar, and get really valuable items. Sell them all to him. Now, go near the Dawnstar mine entrance and you'll see a cluster of 3 rocks to the left, near a small tree. Crouch and look in the middle of these rocks and there will be an invisible chest, holding all of the Khajiit's inventory and money (along with your valuable things). If you take the gold, they won't be able to buy anything else from you, (selling things will get your speech up), so put all your gold inside. Take your valuable items and sell them again, rinse and repeat. Eventually when your speech is high, you can take all the gold. I did this one in about an hour an a half, but it works like a treat.
Smithing — For smithing you need the Transmute spell and Alteration spell. When you have those, gather all of the iron, silver and gold ore & ingots that you see in Skyrim. A lot of mines have these lying around, and smiths from major cities.
You can also do the exploit of buying from a shopkeeper, saving, hitting the same shopkeeper, and loading the save again to restock her inventory while keeping the items. If this is too much weight for you, give it to a follower. You can even give him rings and armor to let him have more carry strength. Now go to any smith in Skyrim with a smelter and an anvil, (I used my home at Windstead Manor, but the one in Windhelm works just as good.) Put all the ore and ingots in your inventory. Equip the transmute spell on both hands and continue to spam it and then wait (to regain magika). Doing this will turn your iron into silver, and silver into gold. Smelt all the gold ore afterwards, and go to the anvil>jewelry>gold ring. Now you'll have a lot of gold rings in your inventory, which you can sell and possibly even use for the speech section. Again, if there's too much weight, give them to a follower.
Illusion — I literally sat there spamming muffle on both hands and waiting while crouched.
Lock Picking — For this one do not use the tower stone as using it on locks gives away precious lock picking exp. Instead, pick all the locks you can find, even if they're out of your way, and collect all lockpicks you find. You can also use the shop exploit I talked about earlier to continue buying lockpicks from almost every shopkeeper. Go to Calcelmo's museum in Markarth for a lot of locks to pick, varying in difficulty. It will be considered trespassing unless he gives you the museum key. (Pick it first while sneaking unless you have the perk, then get the key.)
Sneak — Basically just be sneaking in every dungeon. Getting sneak attacks also helps your exp bar.
One-handed, Two-handed, Conjuration, light/heavy armor should come naturally based on your play style. I use the Mace of Molag Bal, Ethereal Shield, Namira's Ring, Krosis, Waterwalking Boots and the upgraded Thieves Guild set which you get for completing the Thieves Guild quest line. This got me light and heavy armor exp, lots of useful perks and skills, one-handed exp, block expand even sneak exp. Use whatever you fancy, but Skyrim was a breeze after getting this set.
NOTE — I used Skyrim: Special Addition with no mods, so I'm not sure if you need the DLC's for these.