What are some techiniques that can increase your chances of getting rarer cards in Yu-gi-oh booster packs....?

Question

Like secret rares, ultimates, etc.

Answer 1

You could take an electronic scale to a store and weight the packs.  Booster packs that contain rare cards sometimes weight .1 or .2 grams more than normal packs.  Except you can't detect ultimate rares as they are only slightly heavier than normal cards.