Step 0: Have a friend do a mock interview with you.
Tell your friend to pick a question like the ones you've been getting.
Solve it on a whiteboard.
In addition to getting some scenario practice, your friend can point out if you're coming across in an awkward way.
Step 1: Listen
Listening is more important than talking in good communication.
I interview a lot of software engineers. Sometimes candidates get so excited about an idea they have that I can't get a word in edge ways to point out they missed a requirement or to suggest there's an easier solution. They may leave the interview saying "I cranked out some great sorting code," but in my notes is written "Implemented bubble sort."
Before diving in to code, verify that the interviewer wants you to implement something. If they say "How would you sort the data," you might not need to implement a sort algorithm.
Step 2: Think Out Loud
If a solution to a problem occurs to you, say it so the interviewer knows where you are.
If they ask questions about your thought, follow their line.
If they just acknowledge what you said, analyze it for a minute and see if it's a good solution, or if there are interesting caveats.