Hi Eric,
Getting stuck between two answer choices is never fun, but it's an incredibly common predicament. If you find yourself in a tight spot, it's by design: more often than not, one of the incorrect answer choices is specifically designed to be significantly more attractive than any of the other three incorrect answer choices, and you are tested on your ability to tell them apart. So, how do you do that?
As Emily pointed out, the optimal means of differentiation will vary by question type: Let's say you're solving an Assumption question. If you're stuck between two answer choices, apply the Assumption Negation technique and see which answer choice, when negated, weakens the conclusion of the argument. Or, maybe you're debating between two attractive answers to a Point at Issue question: apply the Agree/Disagree test and determine which answer choice is such that one speakers would agree with it, and the other speaker would not. In other words, for most LR question types, there is a question type-specific test designed specifically to help you differentiate between the correct and the incorrect answer choices.
So, you may wonder - is that the best you can do here? And the answer is a resounding NO! The very fact that you found an incorrect answer choice attractive is already problematic: it means you've been caught in the trap, and you need to find a way out of it. You can use the aforementioned tests to do that, but why did you get trapped there in the first place? Because you did not prephrase the answer on your own! The absolute best thing you can do to avoid this predicament is to prephrase the nature of the correct answer choice
before you look at the answers: if you know what you're looking for, you will never, EVER find an incorrect answer choice even remotely attractive! And even if none of the answer choices represents an exact match for your prephrase, having speculated on what the right answer choice would have to say (or do) is already incredibly helpful! Use that prephrase as a filter - or a lens, if you will - through which to examine all contenders.
By learning to prephrase religiously, you will greatly reduce the risk of getting stuck between two answer choices. It will still happen, but a lot less often. If and when you do, think of the question-type specific tests that you've learned in class. More often than not, they will provide you with the roadmap to the correct answer choice.
Hope this helps! And good luck