First, we've been hosting for exactly one time. So, this is from a personal perspective and not an experienced one.
Don't overthink it. The beauty and fun..and even the slight competitive side of hosting is personal service you provide your guests, your way. That's what sets your BnB apart from others...you. The things you do for your guests give your BnB the particular character and culture you want.
Leave em gift. Don't leave em a gift.
Turn down service. No turn down service.
Put a mint on the pillow or don't.
Leave a bowl of fruit in the room. Or don't.
Fresh flowers. Vacuum and make the bed daily. Fresh towels perhaps? How about a basket of disposable toiletries for the use? A card when they depart? A follow up thank you note or email?
All these things are touches of service I have encountered in my travels here and there. Some we've adopted in our BnB, taylored to our vision of charm and service.
You should absolutely do the same! Experiment and have fun with it! Your guests are airbnb guests. They expect a level of different in every place they stay and appreciate it!
Good luck! And keep up the great hosting!