I read Dr. Cynthia Baum-Baker's blog on Psychology Today and appreciated her take on how couples can utilize wisdom to get through these challenging times.  I used her list as the basis for adding my own thoughts to her perspective.

Pragmatism: Be discerning. Not every irritation needs to be discussed or pointed out.  Practice letting go.  Sleep on it.  If it still lingers in the morning maybe talk about it then.  No blame.  Just a simple "When you do X, I feel Y."  
Balanced Paradox: We all need connection as well as autonomy.  Make sure you allow for separate time. Structure in activities that connect the two of you, even if it's just for a few minutes.
Cognitive-Affective Differentiation: Acknowledge your differences - some are more prone to feeling, others take comfort in thinking.  Accept these differences.  Some people tend to let their energy expand; others tend to contract under stress.  Neither style is "right".
Affect Optimization: Watch for our negative bias, our tendency to focus on frustration.  Notice this, allow for it, then reflect on it.  Often we personalize things, but many times our partner's behavior has very little to do with us.  Sometimes we wish it would!  Express appreciations.  Practice gratitude for what you have, for who you are.  Search for the positive and if we need to express frustration, find the hurt underneath our anger when we express our emotions.  
Emotional Generosity: Value imperfection and seek patience, humility, and the ability to say a quick "I'm sorry".  It doesn't mean you did anything wrong, but just that you acknowledge your partner's suffering. See their wounding that lies deep within, maybe not even expressed.