Let me just start by saying that I love my boyfriend very much and we're so similar that sometimes it's scary. However, spending 15 months together in a tiny space has a way of highlighting the differences in how we approach different situations and how much work a relationship can really be. Adjusting to accommodating someone else is never easy and here are some of the lessons I've learned (and am still trying to perfect).
Who could stay mad at this face :)
1) Count to five before you speak. The wrong remark or the right remark with the wrong attitude can spark an argument or be conveyed in a less than desirable way.
2) Learn to pick you battles strategically. Just because you've always done some trivial thing - like loading the dishwasher - a certain way doesn't mean you need to tell/harp on/nag your significant other or roommate to follow your lead. You can adjust to a new way of doing things. Sometimes the adjustment is long and painful but it's the best thing in the long run.
3) You do not always need to be right. Correcting what someone says or does and getting the last word should not be the most important thing. The most important thing is getting along and being happy and living a stress free life. There is no need to add stress if you don't have to.
4) Keep open lines of communication. This home belongs to both of you and both of you need to feel comfortable in it all the time. If you keep your emotions and feeling inside then you will eventually resent the other and at that point it's much harder to come back from it. NOTE: When keeping an open line of communication, please refer to lessons number 1, 2, and 3 :)