How do you fight?

1. What's the point? Remember, when you're talking about things...always remember what the bigger purpose is. For us, it's about the Gospel of Jesus Christ. Don't forget that our life here is temporary and we look forward to a future when all things are made new. I know that when people are living in their selfish, prideful bodies...they tend to focus on what is right in front of them. They let their emotions own them and they totally forget why there were arguing in the first place. Don't forget the bigger picture.
2. Issue not Person: When you're talking with people it's way too easy to make everything personal. Emotions fly and things go everywhere. When you argue...argue the issue, not the person. Don't make up things that are not there or that you don't know about. We tend to do that when we make assumptions as to how they think or what they do. The worst part is when we go on making all these conclusions and speculations as to what we "think" they are/will doing/do. Also, when you are talking with the person...go to that person. Third-party arguments (i.e. hearing from other sources, email, texting) are a shallow substitute for actual dialogue. Beware of thinking the worst of the other person. Be quick to show grace and forgiveness. 
3. Study for yourself: When you're dealing with an issue...make sure you have studied it yourself. It's always kinda weird when I hear someone explaining something and it's totally wrong. Make sure you have read the thing in its right context. Be fair when you present both sides of the argument. But more importantly...come to a conviction about your stance on your own rather than following someone else's opinion. You need to, at the end of the day, have your own thoughts about things...this is where study comes into play. Yes it's hard and tedious to go and learn yourself...but it's how we grow.
4. Be flexibly solid: As you study more and more and as the Holy Spirit continues to reveal truths to you...you're going to develop convictions about things. It's what you believe. You've studied it and you've come to your conclusion. That's a good thing. However, always be open to refining and shaping your thoughts. You might not have considered the other side of the argument. Allow for some flexibility to change when you come across something that might challenge you.
5. Fight like family: When you discuss topics...remember who you are dealing with. If they are believers in Jesus Christ...it's family. Yes you might disagree with them on how they interpret things...but in the end, they are your brothers and sisters and you can and will worship with them for eternity. Don't you ever elevate certain parts of your theology at the expense of other theology. Like don't get all worked up about "limited atonement" or "unlimited atonement" and neglect Romans 12:10 where it says "love one another with brotherly love". Your heart matters whens you talk about things. Don't forget that you are also commanded to equip and train the saints for the work of the ministry.
6. The Goal: Just like the first point...the goal of you arguing things (if there is a bigger purpose) is NOT to win. If all you want to do is win the argument...then your heart is wrong. Because you don't care about the other person and maybe you've made up all these things about them...and you just want to prove that either you're right or they are wrong. Your heart is off. What's the purpose then of arguments? Ultimately for the refining and sanctification of the Church. The point of conflict in Matthew 18 is restoration and reconciliation. That is your end goal....not to win your argument.