I'm not great at soothing myself generally, but if I really need a pick me up I like to cook or bake/make something simple if I can. My favourite go to recipes are homemade cookies, a pizza or homemade ice cream. The advantage of the ice cream is that it doesn't involve any cooking or preparation really and only consists of 3 ingredients, so hard to get wrong. And even if you do get it wrong, it still ends up being delicious.
If those are not an option because I'm too ill/lethargic/in pain and I have money to spare, I might treat myself to something small instead, like my favourite jar of hot chocolate with some mini marshmallows.
II'll watch my favourite shows (anime can be a particularly good distraction for me, or any type of animated show/movie) or animal videos.
I also still have my old Gameboy and Pokémon Yellow - I've had this Pokémon Yellow since it was first released and it still works! Sometimes that's a good distraction, but easy to play.