A new planet is always exciting! This is one of the coolest parts of running or playing a game involving travel between the stars. If you think going to a foreign country is an eye-opening experience, wait until there are whole alien planets to get culture shock from.

But since we don't all have experience of alien cultures, it can be difficult to create such worlds for your players to marvel over. There are a few solutions. You can go the Planet of Hats route and give the locals some defining characteristic to make them interesting. Actually... let's just link to this planet trope index and let you explore on your own. You will get tons of ideas for creating new and strange planets from this.

Transcript

Luke: Okay, remember, R2. No active sensors. We can't trust anyone on this planet except Yoda. Assume they're all Imperials.
Luke: We need to maintain cover at all times. Don't go outdoors unless it's absolutely necessary.
Luke: No hacking into computer systems until we can be sure they're not going to hack you back.
Luke: We'll probably need to make contact with the underground to dig out this Yoda guy. It might take us months.
Luke: I just hope we can get him alone.