To level up fast in the First Sea of Blox Fruits, start by completing quests. Finish the starter quest to reach level 10. Then, head to Fountain Island. You can swim faster than boating here and use the wall strategy to level up to 55. Next, visit Pirate Island. Server hop the Diamond chest and Bobby, using the wall strategy to reach level 105.
Unlock new skills by purchasing the aura and Sky Junk once you have $35,000. Grind Yeti in Snow Island using Dash and M1, then server hop to the next island. For Marine Fortress, use the wall strategy and server hop until you reach level 220.
At Prison Spin in Jungle, eat any Loi fruit you get and use the wall strategy to kill all bosses. Server hop until level 350. Light Fruit is highly recommended for grinding due to its elemental fruit abilities and fast flight speed. Buddha Fruit, Flame Fruit, and Magma Fruit can also be effective based on your playstyle.
Defeat bosses like Bobby, Yeti, Magma Admiral, Fishman Lord, and Wysper to earn significant XP points. Participate in raid events to earn a lot of XP points. Make sure to go with other players to handle these raids efficiently.
By following these steps, you can level up quickly and efficiently in the First Sea of Blox Fruits. Happy grinding!