Things don’t always run smoothly for adventuring parties.  Even if they’re the best of friends, a tense situation or a misunderstanding can cause conflict.  So, what are some things to consider if you want the heroes to butt heads?

1. Be aware that there are lines that can’t be crossed without the group being completely destroyed.  If you have them begin fighting in such a way that the reader can’t believe they would realistically be allies again then you might have gone too far.  Interparty conflict is there primarily to create character growth and possibly shift the power dynamic.  The only time you should really cross certain lines is if your intention is to destroy the party.
2. There should be some build up for the conflict. If things are going smoothly then you can’t suddenly have them get into a full-on screaming much.  Have some tension appear beforehand.  It can be them nearly dying or getting lost or something that doesn’t even have to do with the party members.  Your heroes need to be under enough stress that it makes sense for them to react to what would be the inner party spark, which could be minor in the grand scheme of what they are dealing with.
3. Conflict doesn’t always have to be overt.  There could be a situation where a member doesn’t trust someone.  So, they begin acting a certain way around them.  This will eventually turn into an open issue, but the conflict can stay under the surface for a while.  It doesn’t even have to explode.  A third party could notice, talk to both allies, and get them to discuss things.
4. There doesn’t always have to be a yelling match or violence.  That is flashier, but that is the extreme finale of party conflict.  Like in real life, things can be settled through a discussion.  It isn’t dramatic, which is why most authors don’t use it much.  Yet, it can work for certain situations.  Some conflicts can be caused by an accidental slight that the annoyed person doesn’t mention.
5. Cursing is not necessary!  Neither is mother insults!
6. Timing is important for a conflict to come to a head.  Having it all happen during a dangerous situation might not make sense even if it increases the tension.  I think people do this under the ‘facing death makes you want to say everything on your mind’ concept.  Yet, it ignores that most people would want to survive and know that their allies being on their side increases their chances.   Pissing off someone who is trying to keep you alive is self-destruction and foolish.  If it fits the character then it works, but it gets done for some who you would think have more sense.
7. A personal issue should fit the personality of the characters involved.  Those who demonstrate a level of pettiness or hold loyalty in high regard are examples of those that can have conflict with less noble allies.  One who is highly forgiving or doesn’t care about underhanded tactics wouldn’t fit very well if they go off on someone over anything short of a major slight.  Even the way that a character goes off needs to fit how they have been acting up until that point.  Otherwise, it feels like the author is doing it solely for the sake of drama and hasn’t thought it out.