1. Develop speech early
Late(r) in the game you will end up with a lot items and selling them is painfully slow if you can't sell any item to any merchant (Merchant perk). To make this even more efficient use an `Investor` perk and with it you can sell lot a more whole lot faster.
2. Develop smiting very early
If you are not a pure mage (let me know if you are, I'd like to know how are you doing) develop smiting completely. With smiting (and enchanting) you can create weapons more powerful then ones you loot or what would you get for completing a quest. For example see my dedric bow.
The problem is that I can't sell it to anyone... Bethesda, can you do something about this? Maybe create an exclusive merchant for really valuable/expensive items?
3. Enchant, enchant, enchant
Enchanting goes hand in hand with smiting. To start with it collect any magic item you can find and disenchant them. That gives you a wide selection of options to use on your weapons and other items. Once fully developed (top perk) you can put two enchantments on an item and that is fun and frustration at the same time. Previously I used capture soul and magicka damage on ebony bow. Now I have paralyze + soul capture. It is fun to see Drugar Deathlord do "planking" when hit by arrow. Frustration comes when you can put enchantment you want to an item you want, e.g. fortify archery can't be applied to torso armour.
4. Make potions, a lot of them
For my style of playing potions are very important. With enough skills (and lot of experimentation) you can make a potion for almost anything. The ones I make a lot are fortification potions for smiting, enchanting archery. On occasion I make a very nasty poison and then I apply it to my meele weapon. I forgot one - carry weight.
5. Vary your tactics
Change your tactics depending on the situation. Recently I have found that I am levelling up slowly, slower than usual. What I was doing was simple - get my powerful bow, sneak in and kill them all while sneaking. It works fine (more than fine - I can kill a giant with single arrow) but it becomes a habit and all of a sudden game can become predictable (or even boring). Remember that spells you learned a while ago but not using it? Maybe it is a rune and having a single, narrow corridor is a perfect place to put one in. Then lure the enemy in and take care of the rest with some other spell.
6. Choose your quests
As any RPG game Skyrim is about making decisions. Stay true to your beliefs and don't do quests you don't like. I will not do Boethiah quest just to get an item. I can forge and enchant better item anyway. Dark Brotherhood quests could be the same.
7. Join the Bard's College
Bard is not really an inviting title/class of player but if you go to Solitude do quests for them. You'll work hard to get the quest item and reward is very good. If you didn't do one I won't spoil it but I'll say reward is not in gold... Also, if you want training in speech you are at the right place.
8. Check your inventory/stash
It is easy to forget what did you find in the cave last week or the spell book you bought. I did forget about some spells and I am trying to use them more now. These are telekinesis, transmute, calm and fury. And ebony skin. I'm sure there is an Azura star somewhere in a chest in one of houses I own...
9. Don't forget the real world
Playing Skyrim is fun and it is so easy to forget to take care of daily things we do like the rubbish out or buy bread and milk for tomorrow. If it easier to remember watch that episode of Big Bang Theory when Penny starts playing Age of Conan...
