Getting a return offer goes far beyond just doing your tasks when they're due. You have to show that you would be a good fit to come back as a full-time employee. This means you should not only have an impressive set of technical skills but also soft skills.
When you receive tasks, don't wait until the deadline to show progress. Make pull requests regularly. This shows you are working consistently and allows your team to give you feedback incrementally.
Actively seek feedback from other people within your team. Show that you are enthusiastic and willing to improve yourself. As an intern, you have significantly less experience than everyone else on your team. Because of this, it's important to show humility and learn from everyone at every opportunity you get.
If you find yourself with more bandwidth, don't coast. Ask for more tasks, study infrastructure diagrams, study concepts, etc. This signal tells the company that you are someone who looks for work rather than waiting to be told what to do.
Being a good coworker is extremely important. Be communicative and social. Go to team lunches, make personal connections, and don't be afraid to ask people for 15-minute coffee chats to learn about their roles. When managers evaluate interns, the number one question they ask is: "Would I be happy to work with this person?"
Make yourself visible to your management. If your company has sprint reviews, volunteer to present your progress. Be active during your daily stand-ups. Send a concise weekly status update to your manager and CC anybody else relevant to your progress, outlining all the things you did in a week. This ensures that when leadership meets to discuss return offers, your name is already familiar and associated with the progress that you made.
While you should strive to mesh with the company culture, you should never tolerate a toxic environment. If you find yourself in a situation where a manager or coworker is making you feel uncomfortable or overly stressed in any way, make it known. Escalate your concerns to your manager or HR. Good companies will have zero-tolerance policies for this kind of behavior and will deal with it appropriately. An internship is a two-way street. It's just as much about you deciding if they are the right company for you as it is deciding whether you're the right intern for them.
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