If bent from a crash you simply cannot reliably get it straight with just a spoke wrench, let alone without experience. The rim is physically bent and only can be reasonably trued after it is carefully bent back. If that isn't done some spokes will be extremely tight and others will have almost no tension.
If the rim is twisted with an "S" bend - goes to the right and then left but does not go right again, you might as well not even try, unless you are willing to put up with a wheel that will always be both somewhat out of true and weak as well.