I hope you have each had a blessed Sunday dwelling in our Lord's word today :)!
In Romans 12:18, we are told to "Repay no one evil for evil, but give thought to do what is honorable in the sight of all".
We are called to be peacemakers. "Blessed are the peacemakers, for they shall be called sons of God." Peter tells us in 1 Peter 3, “Whoever desires to love life and see good days, let him keep his tongue from evil and his lips from speaking deceit; let him turn away from evil and do good; let him seek peace and pursue it. For the eyes of the Lord are on the righteous, and his ears are open to their prayer. But the face of the Lord is against those who do evil.”
Now, "keeping the peace" doesn't mean that if someone does not believe as we do in the bible, we drop all convictions so that those convictions don't clash with this person. Each of us will be held accountable to God in the day of judgement, when God shall judge the secrets of men (Romans 2), and he who "knows the right thing to do and fails to do it, for him it is sin" (James 4). We have to stay grounded in God's word, no matter what others think that word really means (or even if they just think it doesn't matter). If God has not convicted them of the same thing, that doesn't mean we are not being held accountable. Now, the Lord may be calling you to share those convictions, but always in a peaceable way :).
Convictions do come differently to people, though. And 1 Corinthians 10 gives us an example of how this may play out;
"“All things are lawful,” but not all things are helpful. “All things are lawful,” but not all things build up. Let no one seek his own good, but the good of his neighbor. Eat whatever is sold in the meat market without raising any question on the ground of conscience. For “the earth is the Lord’s, and the fullness thereof.” If one of the unbelievers invites you to dinner and you are disposed to go, eat whatever is set before you without raising any question on the ground of conscience. But if someone says to you, “This has been offered in sacrifice,” then do not eat it, for the sake of the one who informed you, and for the sake of conscience— I do not mean your conscience, but his. For why should my liberty be determined by someone else’s conscience? If I partake with thankfulness, why am I denounced because of that for which I give thanks?
So, whether you eat or drink, or whatever you do, do all to the glory of God. Give no offense to Jews or to Greeks or to the church of God, just as I try to please everyone in everything I do, not seeking my own advantage, but that of many, that they may be saved."
Paul did not consider it to be unlawful to eat meat that was sold in the temple. But some of the early Christians did, and Paul's explanation was simple. It was okay to eat it; but if doing so was offensive or was a stumbling block to any of the believers you were dining with, avoid it for their sake.
This isn't to mean that you are to be a different person around different people; it means that part of what makes you who you are as a Christian should be to care more about others than yourself. If you disagree on core biblical truths, never compromise. But if it's just a simple matter, like your friend doesn't listen to certain music, even if you find nothing wrong with the music, don't play it when she is around, as that will be a stumbling block to her conscience! This could go further to include things that might not have anything to do with "doctrine" at all. One person may be fine with certain things, like their living room being trashed by the toddler toys all day long, and only cleaned up when the little one is put in bed for the night. Others may want it kept cleaned up throughout the day. While it may be okay to leave the toys out at the first house during the day, if you don't help keep things picked up in the second, you will be causing frustration, which will not keep the peace.
"Do what is honorable in the sight of all" -not changing who you are, but, through Christ, being characterized by your thoughtfulness of others.
"For from Him and to Him and for Him are all things".