See the current state of the merge/rebase. Check git history, and the conflicting files.
Find the primary sources for each conflict. Understand deeply why each change was made, and what the original intent was. Read the commit messages, check the PRs, check original issues/tickets.
Resolve each hunk. Preserve both intents where possible. Where incompatible, pick the one that better serves the destination state of the codebase. Never blindly choose ours or theirs without understanding intent; if intent is unclear, ask the user before proceeding.
Run relevant tests. After resolving all hunks, run the test suite (or the subset that covers the conflicting areas). All tests must pass before the merge/rebase is marked complete.
Verify the result. Check that the resolved code compiles/type-checks and that the intended behaviour from both branches is present in the result.
Complete the merge/rebase. Stage the resolved files and continue (git merge --continue or git rebase --continue). Write a commit message that describes what was merged and any non-trivial resolution decisions made.

resolving-merge-conflicts