Do you resell or distribute any software to your customers? If you don't, you probably should start offering it.
It's very easy to setup, you can easily create successful profit margins (without price gouging your customers), and begin to compete with the big boy's of IT.
Everything from backup solutions, business management applications, network management solutions, ticketing services, to anti-virus, are all available at relatively affordable prices to you (depends on your distributor). The kicker is that most of these software packages that you can resell, or distribute, will eventually cost you less per month or per year, with the more that you sign up or sell. So as long as you manage your affairs properly, and don't lose customers hand over fist, over time you can not only make everything pay for itself, but you can make quite a bit of money off of it for yourself.
So if you're running a small IT business, and you're daunted by the idea of selling the software you use on a daily basis, don't be. It is an easy way to go about increasing sales.