Look for an agency with a portfolio that includes sites similar in scope and industry to yours, since design and technical needs vary a lot between an e-commerce store, a service business site, or a content-heavy publication. Ask to see live examples rather than just screenshots, so you can test load speed, mobile responsiveness, and navigation firsthand. A strong agency will ask about your goals before jumping into design, whether that's driving sales, generating leads, or simply establishing credibility online. Check what platform they build on, such as WordPress, Webflow, Shopify, or a custom framework, and whether it fits your team's ability to maintain the site afterward. Finally, ask about their process for discovery, revisions, and timeline, since a clear process is often a good predictor of a smooth project.