Experience is critical because making mistakes ends up costing a lot of money.  Bad architecture decisions can have huge impact upon throughputs, etc.<p>Based on my experience, the best way would be to get a job at a medium size systems integration firm.  Your ability to write scripts etc might get your foot in the door.  Then you would have to learn fast from the experienced infrastructure engineers.<p>Of course, you will also need to read a lot and learn a lot about LAN, WAN, SAN, VPN, DNS, firewalls, virtualisation, cloud, etc, etc.