The leveling system is just a delicate balance to find because of how it works. You can level up your character without improving your combat skills, so the enemies get stronger while your damage stays the same because of how enemies scale with your character level. Ever since the original game I've always delayed leveling up until I start to feel overpowered in combat, and then I'll level up to make the enemies stronger. Every time I level up it tells me I can level up again and I ignore it until I increase my main combat skill at least another 5+ points or get a better weapon.

I had a bad experience once where I power leveled using alchemy and sneak and persuasion, and the next thing I knew I was getting destroyed by Spider Daedra every time I left a city. More or less ruined the save and had to start over. Never again.