docs(readme.md): add tips

[lloydchang]

Checklist:

• [x] I have read freeCodeCamp's contribution guidelines.
• [x] My pull request has a descriptive title (not a vague title like Update index.md)

Closes #378

Co-authored-by: Natalia Gill sngill.ca@gmail.com

[lloydchang]

👆 @ngillux Please see above per our Slack conversation in CodeDay Labs at https://codedayorg.slack.com/archives/C05E9LWCYRZ/p1690041029236379 Thank you!

Would you please review #378 and #380 and add a comment that they look good to you? Thank you!

Context: I found your tips in this #natalia-gill channel useful hence I created

• Issue #378
• PR #380

Why: Not all the CodeDayLabs mentees assigned to freeCodeCamp Classroom are in this #natalia-gill channel, hence having your tips in README.md would be helpful to them, and anyone else new to freeCodeCamp Classroom.

Thanks again!