well it depends on which section of the exam you're talking about... in problem solving you can sometimes think through the remaining answers that you have left. also don't forget that if you have to plug in numbers... try extreme cases... not 1,0,-1... in SC we all know the AD/BCE split... which i would say is helpful but everyone knows that strategy, so after you've narrowed it down remember that the GMAT likes for things to be in the active voice... so if you must eliminate one of the remaining choices because it's in passive voice... go ahead and do so...

for me when I study I know that getting hte corect answer is the goal, but if im answering problems in the OG i also leave the last two answers that I had... so I can see if i would have had to guess... if i would have been able to guess one of hte right answers