There's a big difference between a horse doing as you ask and half doing as you ask. This includes catching an unhandled horse for the first time. It should never take weeks or months to catch an unhandled horse. Sneaking around a frightened horse for weeks on end isn't good for the horse or the handler.
If I can't walk into a horse's stable after two or three days and put his halter on, then I've done something wrong.
Give yourself every advantage and have the horse in a small safe stable or yard. If the horse won't allow you to approach, you must place a rope around his neck and use the rope to teach him to stand. This is one of the most difficult things to do in horse training and no one can give you the skill and experience that's needed.
It should never take weeks or months before a horse is confident enough to accept a halter.
My Foal Handling Online Clinic and my Starting a Horse Under Saddle Online Clinic were both filmed over five days. Each horse had two or three twenty minute lessons per day and the results speak for themselves.
My approach has developed from handling thousands of horses. It's not some theory that may or may not work.
If you truly want the best for your horse, don't leave him in the paddock until he's two or three years old. Don't leave him until he's six months old. Handle every foal in the first few weeks of his life and you won't have dramas when he's older.