When you are in conflict there are two really helpful steps you can take.
Step One - Get Clear With Yourself
Write down what they said or did that triggered you.
Convert each of these to make them as neutral as possible - so remove the judgement and stick to the facts.
Now make a list of all the judgements you have around each of these.
Each feeling is caused by a thought, so now write down your feelings for each of the list above.
Now write down what you NEED.
And now what you WANT - in order to get that need met.
Secondly - Phrase it palatably.
Now phrase the above but without the list at number 2.
When you did (1), I felt (3), because I need (4). So how would it be for your to do (5).
This is adapted from NVC.
Please note:1. don't say "I feel...because YOU did..."
If you need help with feelings and needs - please message for the list