Where do you start? Generally the moment you start telling people you are starting your own business you have started your marketing!
The challenge is to tell as many people as possible without having to be standing in front of them, unless you are on stage with an audience of over 1000 people at a time.
And they want to be in the audience listening to what you have to say!
Making the assumption you know everything about marketing is a mistake! Likewise not all marketing campaigns are equal or are they. Same marketing campaign running for 2 different businesses yield the same results?
The best place to start with marketing is to create an activity report and take it from there. There are multiple options and in an ideal world they should all be actively running for you business.