For pixel art I'd say get references. Tutorials are good to a point, learning some techniques, but I think if you look for what you want and try to copy you will get better results than trying to find a specific tutorial (unless you need to learn the painting software too).
If you use Aseprite, you will see it has a lot of palettes. Choose one and stick to it. Try to solve everything in your game with it.
I'm not experienced, but I think my art is better when I limit myself to a few colors. A 16 color palette is enough for retro. If you want something more complex, 32 colors will be enough mostly.
And I say to get a preset because it is something vastly used and works for most of the games.
Keep your sprites small. This one I mean for efficiency, considering the deadline. I'd say don't go bigger than 32x32 or you will have hard time drawing everything.
tl; dr
- Choose a standard color palette with few colors
- Get references
- Try no to do big sprites
I'm not a pro, but I've been using those rules when making pixel art and I've been happy with I achieve (I don't intend go pro, but I try to improve my art each game I do).
I enjoyed the beds btw! Good luck!