simples ... tsk
make sure that you dont accept bits of paper with messages etc and just point them to online intranet system helpdesk
I said reception as it covers the idea that your a one man band and you've gone out for lunch, then say, your core switch has failed.
The good thing about most *decent* helpdesk software is that they can do pretty good reports for you which, after 3-6 months of running, you use to create your SLA. It basically says "This is our normal running efficiency and we expect to keep it up. We can only do this by sticking to our rules about how things are logged, prioritised, planned for, funded and dealt with. If we don't keep it up there is probably a good reason for it and it is the job of the $Boss to manage this with other named people having key roles!"
Hmm ... ITIL in 3 sentences?