1. Learn UNIX/LINUX
2. Code in C language
3. Learn to code in more than one Programming Language
It is important for a person in the hacking field to learn more than one programming. There are many programming languages to learn such as Python, JAVA, C++. Free eBooks, tutorials are easily available online.
4. Learn Networking Concepts
Understanding what LAN, WAN, VPN, Firewall is also important.
5. Learn More Than One Operating Systems
6. Learn Cryptography
7. Learn more and more about hacking
8. Experiment A Lot
9. Write Vulnerability (Loop hole program)
Vulnerability is the weakness, loop hole or open door through which you enter the system. Look for vulnerabilities by scanning the system, network etc. Try to write your own and exploit the system.