First take a piece of paper and draw a line down the middle. One one side title it applications, on the other side write administration.
Draw a line below that. Then on the applications side you can write a few things like various software products, programming languages, project design, project leadership, software engineering, quality and testing, desktop support, helpdesk support, applications migration, etc.. Note that on the applications
side of things these things are often moretransportable, i.e. not vendor specific.
On the administration side then write down things like helpdesk support, technical support, troubleshooting, operating systems support, systems administration, database administration, network administration, user support, storage, printers, tape drives, disk drives, servers, pc's, hardware, all kinds of things like that.
Then make a decision which way you want to go.
Then you can draw some lines as far as direction you want to go on the side you choose. The line of growth has to do with the amount of decision making that you'll be doing and the amount of autonomy you'll have. On the lower end, people tell you what to do. On the higher end, you have to figure all that out yourself and you decide.
You really do set the stage for yourself.