Do thorough research:

Research local Roofing Contractors. Use online resources such as review sites to determine their reputation.
Ask for recommendations from family members, friends or neighbors that have recently undergone roofing work. Referrals from friends, family or neighbors can be very valuable.

Verify credentials of the contractor, such as licenses, certifications, and insurance coverage. To protect you in the event of an accident or damage, a legitimate contractor must be licensed and insured.
Assess experience and expertise:

In roofing projects, experience is crucial. Choose contractors who have a track record of success in the roofing industry.
Specialization is also important. Certain contractors are experts in specific roofing materials or project scopes. Make sure the contractor has relevant experience.
Examine past work or portfolios that the contractor has provided. You can get a feel for their style and workmanship by looking at past projects.
Request Detailed Estimates:

Compare written estimates received from different contractors. The estimate should include the project timeline, the materials and labor costs to be used.
Beware of low-quality materials or workmanship if you see a bid that is unusually low. Likewise, quotes that are excessively high may not be worth the price.
A contractor who is transparent will be upfront about these possibilities. Transparent contractors should be up front about these possible outcomes.
Check Reviews and References:

Request references from previous clients, and then follow up. Ask about the overall satisfaction of the client with the contractor’s work. Also, ask how the contractor adhered to deadlines and communicated throughout the project.
Online reviews provide valuable information about the contractor and their customer satisfaction. Be sure to pay attention to patterns or themes that appear in the reviews.
Communication and professionalism:

A successful roofing project requires clear communication. Select a contractor that is responsive to inquiries, attentive to concerns, and who communicates effectively through the entire process.
Professionalism goes beyond communication. Assess the contractor’s punctuality and organization during initial consultations. Also, evaluate their overall demeanor.
Warranty and Guarantee

Ask about the warranties on materials and workmanship. A reputable contractor will stand behind the work they do and provide warranties for a reasonable period of time.
Understanding the terms and conditions, including any limitations or exclusions, of the warranty is important. Clarify the process for addressing any issues or concerns after project completion.