It is well worth the time to pay someone to setup your business in QuickBooks, if you want to get everything up and running right away.
For me, the contract is the big deal, that is where I would lay out EVERYTHING in clear terms. This is where the work goes. My contracts for my professional world take me three days to write, and specify everything I will deliver, including all services. If I were to get back into catering, I would do the same, right down to how many guests I will be serving, how many forks I am going to provide, even how many napkins I intend to provide. The more detailed the contract is, the easier it is to negotiate prices, get paid, make sure you are covered if things go wrong etc...remember...
"oh, I know we said 24 guests, but, my cousin brought her in-laws and we are now 32 guests, you said you would cover the party..."
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"perhaps...but then again...maybe not..."