Check out this Dragon Nest Level Up Video Guide by AltusCogiteGaming
DragonNest – Fast Level up Guide Text Format
Well the 1st chapter of the main story will carry you to level 13ish or 12 in under a few hours. Make sure to do the majority of these on easy/normal to reduce time spent. You will find soloing these dungeons will be more worth your time as you do not have to wait around for party members to ready and go back to town. Remember to take up and do all/most of the sidequests along the way, as those will help you level as well as check commissions board for every dungeon.
this can be a little tedious, but you should level to 14 by just finishing up every side quest you have. Make sure to accept commissions as well as returning to field if you want to do another quest nearby.
This is a specific commission that is the best to farm. Temple of sleepers commissions, you will eventually be left with the masters one which is repeatable as much as you want.. giving about 20k EXP in 5 minutes if you do it with a partner/party. Also your job advancement gives out a large amount of exp and should bring you from 0% to 50% on level 15.
This is where you get to do the main story line again. Do however you want at this point, these dungeons are were you get good drops, use your own judgement. I recommend grinding down on easy mode or normal, this is what I did with SoPro and we got through the story in under an hour almost as well as hit level 18. Do commisions with all quests, if you need to grind out level from anywhere 16+ all you have to do is commission from here on out.
Now once you hit 18 you are free to do many things. What i going to get these level for you fast is doing commissions over and over and over again. This might take some time for 24 but it is the fastest way. You can focus on other thing if you want too such a rare items, crafting. Remember once you do a repeatable commision, try your best to return to field and just restart the dungeon and do it again for 30 more k exp. Alot of the commisions give anywhere from 20-40k and that is not including the exp you get in dungeon.
Commission for Sanctuary Nexus Master. This dungeon goes by extremely fast with party/partner and you can finish it and get a good amount of exp to level a well a 37500 from the commission. This dungeon also gives alot of drops you can sell to the market.