How do I decorate this as my entryway?

Depending on the space between the door and the wall... (looks like its not much space), you maybe will NOT have room for a table, but maybe a “live edge” narrow shelf with pretty korbels holding it up. A nice mirror would help with the illusion that it’s a deeper room than it is.

Add something to the floor, that will help seperate the space from the rest of the room.

I am not sure of your space but you could use a console/chest to the right as you walk in the door.

A current and perfect (to me) project is to get an old style door add a shelf or bench to it and hooks for jackets, maybe a mirror. I love the bench idea, personally. You could sit on it and leave your shoes in a "cubby" or basket underneath. Keep soft slippers there to change into. Keeps the incoming dirt down and wear and tear on the floor, too! You can still leave mail there. Hang a basket or two on the hooks, if you prefer. You can stain it, shabby it up, chalk paint it. Anything goes!! https://snapguide.com/guides/make-an-entryway-bench-from-an-old-door/

https://www.bing.com/images/search?q=entrance+made+with+an+old+door+bench&qpvt=entrance+made+with+an+old+door+bench&FORM=IGRE

Plenty of ideas here:

https://www.pinterest.com/pin/265149496790173058/?lp=true

This look (under the above link) looks like it could work well in your space - hard to tell based on only the one photo you posted:

https://www.pinterest.com/pin/627478160557065787/

I immediately thought wall art for the empty wall and then put up rustic shelves from a garage sale or something and paint them, to go with the theme of the wall art.

I would add a coat rack on the wall with a nice mirror, then put a narrow shelf between the couch and the door to define the space.

A narrow console table would work well in this area--rustic, farmhouse style. I got one for my small entryway and another for my narrow hallway off ETSY. (Just do a search for narrow console tables to see what they now have.) Above that a gallery wall of various farmhouse themed items, which could include mirrors if you like--ETSY, Hobby Lobby, any flea market, antiques, collectables type stores in your area could all have things that you could use to put that together. Have fun with it choosing things that immediately upon entering your home will tell visitors "your story" with the things that interest you. On the top of the console table, keep it fairly simple with maybe candles, small books, small décor items, and, if you are a person who needs a landing strip, that can be it with a small tray for keys and such to be tossed into. Personally, I LOVE the lanterns that you can put pillar candles into--I use the battery candles in mine to get the ambiance with safety, and I could see one of those on the floor next to your console table if there is space.

I agree with the hanging shelf with nice corbels. And I would hang the mirror verically not horizontal. I have a shelf like that and it's perfect.