If your snake is fairly small, you'd be amazed at what tiny places they can squeeze into.
Start near where it was last seen, and search with a magnifying glass. Look under, around and inside everything, no matter how unlikely it seems the snake may be there. I've seen pictures of escaped snakes where all you can see is about 2" of snake side, kind of like the where's Waldo pictures.
Snakes will seek out warmth, so check any nearby source of heat.
Keep us posted on your search.
Gale