I find that when I play, I get to around level 50 and then retire. My main skills are maxed out so no more leveling comes from using them. If I switch to new skills, by that time I am severely underpowered. It does make for interesting gameplay at times, but facing a random Ancient Dragon with a new skills in the 20's makes the battle nigh impossible.

I have thought about leveling as many different skills by use as I go, like doing all the guild quests using only the skills associated with those guilds, but have not been able to RP that very well except maybe as a "seeker of all knowledge" type of character. I usually do not pay to level up skills, but maybe I should look at taking that route? (Usually when I DO level up, it is 3-5 levels at a one time )

Another thought is to pay to level up non-essential skills that I may use later on and leveling up as soon as I get a new level, trying make the best use of 5 paid training per level..

Aside from cheats and console commands (I play on PC), how do people get there? I am curious and would like to get all of my 80 perks on one of my characters

Well, the only one who I got to level 81 is my Altmer, Estalenya. She is a perfectionist. She needs to know everything. My other characters are around the 50s and that is where they are going to stay because the untrained skills they have don't suit their character. Just level up the same as all the others I payed for training as much as possible. Money was easy to come by for me. It was actually pretty long an tedious and I don't want to do it again with another character.

I honestly rarely get past level 30. The game simply starts becoming too easy.

So, my recent way to cope with this, is to stop leveling up around lv.19 or so.

Occasionally through the Oghma Infinium, but once through varied gameplay and serious grinding.

grinding

Lots and lots of grinding. Pickpocket and especially Alchemy is a pain in the ass.

Only one of my characters got that high legitimately. The other 20 or so used the Oghma Infinium.

My current is level 49 with no cheats, exploits. He's doing really well.

mine is 52, going to get him to 78, it's going to take a while

Simple.
I don't max out all my main skills at once, just as a result of my play style. For instance, even with a pure warrior build, I'll use the bow, pick locks and do some sneaking - it's not just charging into battle with my two handed clobber-stick. Thus, there is some diversity in my gained experience.
Also, when I buy experience/training, I'll spend the funds for things outside of my main 'line of work.' For example: my warrior might spend funds getting alteration magic training from that dark elve chick in kynesgrove, or something like that.
I currently have a level 61 orc warrior specializing in battle axe and heavy armor who is not yet maxed out on heavy armor. Amazing, but true.
With that particular character, getting to level 81 may prove to be very challenging - I left my magicka at 100 and have poured all my level gains into stamina and health. I suppose I'll need to continue buying experience in magic, and once that becomes insufficient, I'll need to craft heavy armor, rings and necklaces that emphasize magicka points and magicka generation as well as making gazillions of magicka potions, so I can have an artificial reserve of magicka to draw from while I directly employ spells to level up. It will be a chore, but I can do it gradually, I think. There's no rush anyways - this game is much more fun if you enjoy it at leisure, with zero fast travel.

For me, the better question is...

Why do people get to level 81?

I'd find it hard to justify RPing every skill. None the less, some people may lay claim to OCD. However, I'd suspect that most who use the term have no idea what it really means. Therefore, it gets used out of text more often than not.

But for what ever the reason, it can be safe to say that outside of cheating, through the misuse of console commands or glitches, or by turning the difficulty down to use the weaker skills, one must grind it out.

I assume you have several skills in mind to get that high? With the build I'm following, I am ignoring some perks so I can go straight up the Enchanting tree. The build is almost very essential on Destruction and Alteration. Even at level 49, I'm still casting Firebolts and Ebony Flesh now.

Some people require a bit more perks so they usually aim that high.

Actually, no, if a skill gets to 100, I start using another, simple as that. Right now I'm on archery/smithing/light armor, every other warrior talent is 100 already

Ah, okay. So its just the grinding.

yup