1) Get rid of the door knobs, animals, wall mounted TV's and such that caused the dammage in the first place
2) Do not spend more than $200.00 on tools and supplies when for another $300.00 you could hire a professional to do the job.
.3) Do not dry sand as it will sufficate you and do not wet sponge sand because you will be back to dry wall tape before you know it, just tell everyone you have a new idea for textured walls.
4) Do invest in and hang paintable wall liner to cover up the mistakes
5) Next time, hire a professional
How about your last DYI project, care to share?