Now I do like Skyrim a lot but one of the things I don't like about the game is the fact that the entire game world or at least 90-95% of it is level scaled. I do like Level Scaling when it's done right but that also leads me to this, items are also level scaled in terms of when they appear in chests. You aren't going to find a Daedric Sword at level 1 in a chest, the only place to get that at level 1 is the Atronach Forge and a random enchanted one with the exception of the Daedric Bow which you could get an unenchanted one at level 1 but I'm getting a little off topic. The point of the matter is this, Skyrim is not like New Vegas, I won't find high level stuff at low levels so I went a different route. It's something that I refer to as the Helgen Trick or at least I don't think there is an official name for this trick. This trick is best used for Consoles because PC players can just use Console Commands and type a level that they want to be at.
What is this trick well you basically sneak behind Hadvor (You can do it with Ralof but I prefer Hadvor, I'll explain below) and whack him with the iron sword that isn't in the chest, very important that you don't select the chest as it will continue the quest along. This trick will level up One Handed, but more importantly it will level up Sneak which is the main skill that we will be leveling up. You will keep doing this until you get Sneak up to 100 and then Legendary so that you could possibly do it again a 2nd time or start the game at level 18 and a half.The only problem with this trick is that it's extremely repetive, especially if you choose Ralof who will continue to yell "What are you doing", although you can address that and I'll talk about that in the next paragraph. It will take you around 1 hour to level Sneak from 15 to 100, completely worth it in my opinion but it may not be worth it as it's repetive to keep attacking Hadvor in Sneak, backing up for a couple of seconds and then attack him, rinse and repeat. The enemies will also be higher level as well so you need to take that into account.
Now for the stats of the trick and the time. It takes around 15 minutes to go from Sneak 15 to Sneak 60, another 15 to get to Sneak 75 and 30 more minutes to get to Sneak 100. At Sneak 60 you'll be around level 10. At 100 Sneak you'll be Level 18 and halfway to 19. Now the cool part about legendary, if you legendary you can repeat doing this as it only takes 10 minutes to get Sneak up to 50 and you'll be at level 20 by Sneak 44 of your 1st legendary. 1 hour and 10 minutes in and your already at level 20 and can do Pieces of the past immediately, in addition to other quests. You could try for a 2nd legendary however it may or may not be worth it. You'll only be at level 27 by your 2nd legendary of Sneak and 5 more points into sneak after the legendary. I prefer doing this with Hadvor as Ralof is annoying and you need to be quick in grabbing that helgen key which you won't need to worry about with Hadvor. A couple last remarks before my final opinion, you will want to go to settings and turn off voice so that Hadvor/Ralof won't annoy the crap out of you and turn the game difficulty to legendary so that they can't be knocked out due to the fact that the health regen is faster then the DPS that you are outputting. Also don't put any perks into any of the skills, save those for when you are done. If you do then you may be able to knock out Hadvor/Ralof and that will take more time. Lastly if this is a character that you really like, create a permanent save so that you don't have to repeat this and just start the game with this character at level 18 1/2, Level 20, Level 27 or higher although I think you may want to start playing the game at that point. One handed will be at around 35 after your 1st legendary and 43 after your 2nd. Not a big deal and that could be helpful depending on your build.
My final thoughts, I really do like this trick as it addresses the crap items at low level problem that I do have with Skyrim (I found a glass sword within 5 minutes of exiting Helgen) and it also makes the game tougher due to the higher level enemies. It's also good for roleplaying as enemies aren't suddenly appearing in the world. It can be repetive but if you turn the voice sound off and put some music in the background it can make this much easier to do.