The best technique for avoiding the need to request undeletion is to avoid having questions closed. One of the best techniques for avoiding question-closure is to write questions that resist closing. The question in question is still unclear. If an exchange in the comments leads you to a deeper understanding of what leads to unclarity, the question itself has to be edited, possibly radically, to become clear.
[EDIT]Alenanno's comment points to the problem that fixing your question can make the helpful answers and comments contextually incomprehensible and subject to deletion or downvoting as "not an answer". My opinion is that all revisions of substance to a question should be carried out in a manner that preserves the original, such as putting an "Edit" tag in the text. Given the structure of SE, that I think is the only way to preserve the value of a good answer to a bad but improvable question.