I advice against using the same gender for every word. It might well give the impression that you don't even try to learn and in addition makes you forget the proper case for the other genders.
The alternative is to start to learn and practice a few of the linked heuristics (e.g. -ung, -heit, -chen, abstract vs. concrete) and add them. For the rest of the words guess, of course (and no, you don't have to guess the same each time to call it guessing).