Find companies that have experience in developing projects in the industry you need, and check out the portfolio.
Pay attention to the feedback from previous customers, and not only the one that represents the official website of the company.
Feel free to question representatives of those businesses in your field, whose achievements and results motivate you, about their experience in choosing a software application development company.
Check out the company accounts on social networks.
Assess the level of expertise: read publications on the site, articles, watch speeches of top managers of the company at professional conferences.