One does not simply "hide" a body. You must dispose of it.
First of all, you have to make yourself look completely innocent.
After you are the least suspected, you can either burn the body in a fireplace, bury it and mark it with someone else's gravestone, or anything else that won't get you caught.
An alternative is to plant it in a field, and call the police, directly after you planted it, and tell them you found a dead body in said field.
