How to seal the doorway on my room

I got the room done and now i need a new way to seal the doorway from light leaks and smell any ideas i got filters but im looking at the outside the door

Look for foam weatherstripping; they sell it for exterior windows and doors. It comes in rolls of 10', 25', 50', etc... and has an adhesive backing. For underneath the door you can get a threshold and a rubber door sweep. They are both cheap and sold ant most hardware stores.

I came up with a super easy solution to this problem and works perfectly. Take a king size black bed sheet (real cheap at Wal-Mart) and fold it in half. Then nail it down into the top of the door frame. When you shut the door to the room just tuck the sheet into the bottom corner. It will hang over the door and seal the light in all the cracks if you do it right. Most of the smell too, but I get some coming through the A/C ducting still.