Proof Flawless

What tools do you need and what steps must you take in order to mistake-proof painting a room?
I am planning on painting my bedroom with my father. We do not want to call the professionals, as it is too expensive for a job that we are capable of.
What tools should we acquire to mistake-proof the job?
Are there any specific techniques, methods, or steps we should follow for a flawless finish?
Any tips on getting the perfectly painted room?
Thank you!
There is no way to mistake proof anything. However, there are techniques to follow that minimize mistakes.
First, tape off the trim. There is a paper/tape combination you can use. It’s about 5″ wide, and one edge is adhesive. Tape along the top of the base where it meets the wall, and let it drape down over the baseboards. For door and window casing, use 1-1/2″ or 2″ wide blue painters tape. Use that also to tape around your light fixture.
For tools, you will need a 2-1/2″ sash brush (the angled bottom type), a roller with 2 sleeves-one for the ceiling, one for the walls. If the walls and ceiling are he same color, you only need one. A 4″ roller and handle will also come in handy. You will need a tray, the bigger the better. You can also pick up some disposable tray liners for about $1.50 each if you like.
If the ceiling is a different color, start there. Use the 4″ roller to cut along the walls. Cut around the light with the brush, then come out a little further with the 4″ roller. Push your furniture to the middle of the room and cover with plastic. Once it is cut in, roll the ceiling, making sure to cover well and to not leave lap marks. When cutting along the wall, it’s OK to get some on the wall since you will paint over it later. When the ceiling is done, clean your brush and take a break.
Now lay a runner tarp (4′ x 15′) along the wall. The next part is dependent on how steady your hand is. If you think you can do it, use the brush to cut the wall into the ceiling. wet the tips of the bristles and use the angle to “push” the paint up until it just touches. This will take a little getting used to, but if you are using a good brush like a Purdy or a Wooster, it will be relatively easy. If you are using flat paint, you can cut the entire room, then come back and roll. With satin or semi-gloss, cut in one wall, then roll. After you finish the top, cut the base in. Then you can cut the corners with the 4″ roller and a clean sleeve. Finish by rolling the rest of the wall. If you are not comfortable freehand cutting the ceiling, you will need to let the paint dry overnight, then tape it off. Work your way around the rest of the room. After you finish, put the excess paint in the can, mark it for what room it is, toss the pan liners and the sleeves, clean your brush, then it’s beer thirty. Enjoy! Hope this helps.
Here is your proof!!! (Flawless TDM 20-0 Gameplay/Commentary)