Every day, do the daily events: Sakura Class, Escorts, guild Boss, and different fighting events, etc., and get rewards according to your ranking.
Also, take advantage of the double rewards for your escorts between 11 am - 1 pm and 11 pm - 0 am. You can find the Events list on the Konoha map in Events.
Each day, do the Naruto Exercise as well: complete the tasks to get rewards.
Also, complete the Clan tasks to get XP, rewards like 1 Ult Ninja Spirit.
You can also gain XP by completing the Daily 300 and 10 Team Exercising.