Genshin Impact – How Much Companionship Experience Needed Per Rank

Based on my own experience and testing, every member in your party will gain the Character EXP when defeating monsters.

I tested this by keeping track of my party member’s experience points and then fighting monsters in the over-world. After defeating a few enemies and re-checking my character, all four members of the party’s experience points had increased

1. Do daily commissions. Completing daily commissions and the bonus yields 1300 exp per day.
2. Use Resin whenever possible. Resin converts at a ratio of 5 exp:1 Resin, so it doesn't matter what activity you do so long as you spend it.
3. Complete as many single-time Domains as you can. Certain domains found around Tevyat can only be cleared once, but grants exp for doing so.
4. Complete the Experience Book objectives as much as possible. Each entry grants 100 exp and can go a long way towards ranking up.

5. Complete as many side quests and story quests as you can. Story quests are often the greatest source of exp as they can grant anywhere from 300-2000 exp depending on the chain.

6. Explore the world -- you are bound to find many chests and puzzles yielding chests just by exploring Mondstadt and Liyue. Chests can grant anywhere from 10-30 exp based on their rarity.

7. Collect those Geoculi and Anemoculi! Ranking up the Statues of the Seven to rank 10 can yield lots of exp, in addition to boosting your max stamina.