1. Notice it, note it, don't make it worse
Write down what you're seeing, take reasonable steps to prevent further damage if it's safe to do so, and gather any relevant background — prior leaks, past repairs, recent storms — that might explain it.
2. Look at the whole house, not just the spot
What you can see is rarely the full extent of it. A plan that actually holds up accounts for how water is getting in, humidity levels, the condition of the affected materials, containment during the work, and confirming everything checks out afterward.
3. Put the scope in writing
Get clarity in writing on prep work, how the space will be protected, materials to be used, access logistics, permits, testing, cleanup, finish restoration, what's excluded, and how change orders would be handled.
4. Compare more than the bottom line
Check credentials, then look past the total price to how each provider arrived at their number and what is and isn't included in their proposal.
5. Check the closeout, not just the invoice
Before calling it done, confirm what testing was performed, that cleanup is thorough, that you have documentation in hand, what the warranty actually covers, and what maintenance responsibilities fall to you going forward.