Best Way to Prepare for CTF?

The author of the post mentions that a major Capture The Flag (CTF) competition will take place in their city in five days. They have already solved about 100 problems on picoCTF and participated in four online CTFs, ranking in the top 30% each time. They are having difficulties with Crypto and pwn challenges, as well as HARD challenges, mainly in the web and rev categories. They are seeking advice and resources to better approach these complex challenges and discover new exploitation techniques used in CTF competitions.