Unique Amenities: As others have said, it will depend a lot on the area. Best advice I can give, get setup on Pricelabs or a similar pricing/analysis software. They have a Market Research feature I use all the time. Setup your filter to show you properties similar to what your looking for in the area your looking for (size, # beds/baths, etc.). Sort by revenue and check out the listings of all the top performing properties and see what amenities they are providing. I do this often just to stay up to date with what others in the area are doing amenity-wise. We found in our research that even at the increased price-point, a mountain view is worth its weight in gold. We shopped for properties based on that and it has paid off.
Guest Experience: Similar to what others have said, have good detailed automated messages for guests and a guidebook, nothing they hate more than getting to a property and being confused about how to get in, where to find things, etc. We also send an automated message to them around noon time the day after check-in just to see if they have any questions or need anything, most guests really appreciate us checking in with them, this also avoids the common scenario of guests that have an issue at the property but just choose not to tell you about it, then leave a bad review without giving you a chance to make things right. We often get a reply like "Everything's great but the coffee maker isn't working" which gives us a chance to have a new one dropped off and get ahead of any issues.
We also provide toiletries and basic cooking needs to all guests. Just the basics, little shampoo, conditioner, soap and lotion bottles in each bathroom, salt, pepper, cooking spray, coffee grounds, etc.. If you buy them online in bulk they're really cheap and I think it makes a huge difference.
Lastly, DoorDash and other apps like it are incredibly useful. Guests are always amazed at how quickly we get them things they need. Guest runs out of coffee, runs out of toilet paper, needs more towels, etc, we can usually get them any of these things in under an hour with the delivery service, and for much cheaper than the typical service call to try and have your cleaner stop by. We get alot of great reviews specifically mentioning how quickly we were able to get them supplies.
Seasonal Strategies: For us this has been all about pricing. We struggled in the down months during our first year. We decided to price our down months more aggressively and start our discounting 3+ months out. Our lead times and occupancy rates went up a ton in our quieter months after doing this. VRBO's Market Maker tool is awesome for this. I pay close attention to it in down months. It has a graph that shows you where your nightly rate is compared to the average rate of booked properties in your area. As we approach slow months I manually adjust my pricing to try and always stay just below the booked property line.