Morrowind - Easy skills to train

Destruction - cast spells and you will master this skill in no time

Hand-to-hand - Attack some creatures with your bare hands like nix hounds and netch bulls.

Heavy Armor(medium, unarmored) - Let a weak creature attack you while wearing armor (if you want you can turn on infinite health)

Acrobatics - Jump up hills and staircases repeatedly to quickly get level ups in this skill.

Athletics - Run a lot or better yet, swim.

Long Blade - Use a longsword or a broadsword and go somewhere with plenty of enemies (a cavern, town, etc.)

note: I don't reccomend trainers to you unless you are very rich, they charge far too much money, it's better to train the skill yourself.