You can solve the puzzles solo but doing the same with a team is much more fun. For any CTF there will be multiple challenges open, so that everyone can work on their own as well as collaborate :)
Google as much as you can.
You might get stuck at some problems which is fine. You can contact the author/fellow contestants for help.You might glearn about a few more resources or you could check if you are on the right path.
Take a Break or solve a different problem if you are still stuck.
Be thorough with Linux commands like grep, file, strings, uniq, sed, awk.
Set up to run VMs so that you can use Windows or linux or (whatever the problem requires) / (u prefer).
Keep an eye for Buffer Overflow(like Integer Overflow).
Examples of small vulnerable C programs & Examples of lots of vulnerablities - Wireshark