Tip 1 : Practice a lot of data structures based questions, this is the most important part of the interviews/tests of any company.Solve atleast 200 questions on GeeksforGeeks or LeetCode.You can sort the questions company or topic wise.A month before the hiring process starts, I gave several coding contests on Coding Ninjas.Try giving as many such contests as possible.
I also attended many live webinars of Coding Ninjas of topics Backtracking, Algorithms, etc. which helped me a lot in brushing up my skills and cleared my concepts to a great extent.How to Ace your coding interview hosted by them was also really insighful.
Tip 2 : Confidence is the key to crack any interview.If stuck on any question, just ask for hints.The interviewers are mostly really helpful.Also, do keep on telling them whatever approach you have in mind.
Tip 3 : Strengthen your concepts of DBMS and OOPs.These are very important subjects and should be revised a day before the interview!

Tip 1: A good resume includes your skills, projects and experience(internships/volunteer/academic).One should have at-least 2 decent projects.These could be web/app or even python/c based projects.You should be thorough with each and every project you've mentioned.
Tip 2: The resume should be well-formatted.Do not mention things you aren't confident about.Mention your core subjects as well.Write only what you know!