I didn't think before that having too many colours is a bad thing? Generally, in cases where I make something like this piece, I don't really care how many colours I use or not.

But thank you for the corners and outlines advice! I think that is very helpful and I will keep it in mind for the next time I make isometrics. 

thanks for the suggestion ! i'll keep it in mind 

Very cute! But the same dark red outline on everything is a little harsh. Try changing the outline color to fit with each object.

I like this, good composition and lovely colors!

Unfortunately, there are 747 of them :(
Hundreds are used for 1 or 2 pixels only, with many semi-tranparencies. You used the wrong tool (</=99% transp pencil?) at some point, probably accidentally since they're not obvious on visual inspection.

I'd recommend redoing it by tracing the piece with a set palette of the ~32 of most used colors.

You have some corners issues, which are always annoying in iso pixel-art. The recommended solution is the 3-px corner like you did on the wardrobe. 5-px is too long and doens't look great. Same kind of issue on the left / right carpet corners.

At some point you should start thinking about reducing your use of outlines. They often hinder more than help, for instnace in small details where they look messy. Also try replacing them with highlights in some areas like fabric covers, etc.

You're doing this mostly right, keep at it!