trunks.. go away. please.
there are 3 ways to get experience to level up. one way is going to places you havent been before, you get a small amount of experience, but it's still experience. another way is doing quests. there are a variety of quests, easy and hard, and they all give you a certain amount of exp. the harder the quest, the more exp. finally, you have plain killing monsters. you go around killing every monster you can that's around your level. it may seem boring, but it isnt because you can get good items from them, and improve your profession skills or your combat skills.
you cant really explore super far without leveling. you need to have a good level unless you want to die by the monsters around you. fear not, leveling isnt that boring. sometimes you get bonuses, like rested, and you get 200% experience from killing things for a short amount of time. you don't lose experience if you die, only durability. you will never need to worry about losing your level.
the best way to level for me is just grinding and killing monsters. i kill them and i get money and items. i can either use the items or sell them at the auction house. yeah, sometimes it takes a long time to level, but you can alternate between grinding and questing.
questing is a great way to level up. easy quests can help you if you want to do a lot of them, and then there are harder quests that take a little longer, but you get rewarded for that. by doing quests, you can get some pretty good items. heck, a lot of good items. you also level up because you need to kill monsters in some quests. actually, i love questing as much as grinding.
it's a personal reference for which way you like to level up, but they are all fun, if you want to have fun, do quests. most quests you can do alone, but you will need to party up. partying up isnt that bad. finding groups is harder. it's all ok. i like it.