Getting a summer internship for an international student is a difficult task, as many companies look for full-time candidates. But, the best tip I can provide is to have a resume prepared with all your experience, project, and tech stack, properly word phrased with as many verbs, as meaningful and short as possible, In Addition, apply to at least 200 companies and more through LinkedIn, Companies Career’s pages, Google Careers, and others, Lastly, network, not only LinkedIn networking but, if you have an option to go to conferences, build relationships, not only connecting on Linkedin. There is a difference between networking and relationship. Relationship will stand and help you and makes you remembered, networking is just another number on LinkedIn.
Maybe also, talk to as many professors as possible, they will be having corporate connections, and there is a possibility of referring you to the companies, and that is a really good chance of getting a summer internship, and for this to happen, you should have an awesome resume.
There are so many resume tips and tricks that are available online. One major I want to point out is the Harvard Resume Tips and Tricks.