There are different ways to level up, I will explain to you all the different ways you can use.
The first way to level is doing daily quest, you can get them from west archosaur or Astral world. Each quest will give you different amount of experience but should start with NPC- Quest Master (527, 644).
Talk with the NPC and take all the quest he has, this quest will give you exp and also rewards that you can use to gear up.
Armor and Blood: You just need to kill 50 mobs of each one, they are easy to kill and will also drop silver and bronze scrolls.
Mercenaries: These guys are a little bit hard you should be able to kill them easily but try not to pull more than two or you might die.
Dantalion: This boss is easy you should be able to kill it but it could take some time as it has high hp for your gear.
Cube Challenge: You have to finish cube of fate till floor 50, is easy if you know how to do each floor. Please check the guide on the following link: https://pwi.gamepedia.com/Cube_of_Fate
Alien Contact: These guys are annoying; they have high damage and will silence you all the time you can try to do this but it might be a problem if your gear is not good enough.
To get to these aliens you have to speak with NPC – Teleport Master [PVE] (528, 645) and select Tropical island.
There is no auto path for these mobs but you can use the cords (374, 521)
The next NPC is located in Dream world, to go to the dream world you have to talk with the NPC – Teleport between Worlds (527, 640) and click on the second option.
You will be ported to the Dream World, now you just need to find the NPC- Chief Cook (400, 562)
Take all the quest he has but About Astral Restaurant. These quests are mainly focused on experience.
Best Spices: This quest will ask you to dig some herbs, just click on the auto-path and dig 30 of them.
Italian Cheese: Same as the first quest just dig 30 herbs.
Rabbit Rescue: Easy mobs just don´t pull more than two or three they have high damage.
Slow Roasted Rabbit: Same as other mobs in this area high damage but low hp.
Seafood For a Restaurant: Easy mobs just high damage.
Other way to level up is to do Phoenix Valley, for this just go to Archosaur East and talk with the NPC – Khoan the Survivor (571, 646)
You can find a guide of the Phoenix Valley on the following link https://pwi.gamepedia.com/Phoenix_Valley remember that you can only do this once per day, try to use hyper stones and training esoterica’s to get more exp. This is probably the best way to level up if you have multiple alts and can use them to open the cave.
There are also some repeatable quest you can do as many times you want, for these you need to go to the NPC- Teleport Master [PvE] and select The Spring Area.
Click on it and you will be teleported in front of two NPCs, NPC – Kimberly and NPC – Sky Dweller. Take all the quest they have.
These quests will show in a pink color on your quest tab.
Snowgrind Fox : Go to (394, 539) you will see a portal, go through it and you will be ported to the cave, all the mobs are easy to kill and at the end you will find the Snowgrind Fox you can´t do this in squad, if you are in a squad even if they are not inside the cave it will not count.
Xaphan: Easy mobs around the area, you can kill them easily.
For Sedation: Dig 30 herbs, they are all around the map.
Desecrating the river: This boss is easy, just have high hp. Need to have your armor and weapon refined to level 9 otherwise will kill you.
All the mobs in the Spring area gives a good amount of experience you can also use Hyper stones and Training Esoterica’s to get more exp.
Let’s move to the next NPC – Good Lemur (530, 652) West Archosaur. This NPC will give you quest called Calm Down, this is an easy quest you just need to wait.
Talk with the NPC and get the quest, it will ask you to bring Calmdownshifting, for this item just talk with the Good Lemur again and select the first option.
You will see it will give you the option to craft some items, you need to craft them in order. The last one is the Calmdownshifting but you need to make all the others first, each item will take more time than the other but is basically just wait.
There are two weekly quest you can do, in order to do this, you need to be level 103 at least and you can take them from the NPC - Quest master (527, 644).
These two are a bit hard, the first one it will ask you to kill Borobudur Dungeon Lord inside of Abaddon. You can check abaddon guide on the following link: https://pwi.gamepedia.com/Abaddon
The Second quest it will ask you to kill three bosses inside of Seat Of Torment.
These ones are easier but also check the guide on the following link: https://pwi.gamepedia.com/Seat_of_Torment
With all these quests you should be able to level up to 105 in less than a week, once you reach level 105 is time to do the first rebirth, for this just go to the Main Merchant (522, 652). On the Other tab there are two items at the right side of the screen, the first one is for the first rebirth and the second one is for the second rebirth, each item will contain the item to rebirth and also and box with experience you can use to level up till level 100.
Once you have the item you will need to go to the Master of Cycles (532, 654)
Talk with him and take the quest, if you have the item on your inventory it will rebirth your character and reset you to level 1, use the exp box you get and you will be level 100 again. Remember to update your attributes “C” again as they will reset. You have to rebirth two times and they will give you the option to get more quests, rewards and access to the last cave to farm Emperor.