Hearing little from anyone else, let me tell you what little (I think) I know about trademarks (at least in the US).
Immediately start using a small superscript TM beside your logo. That indicates an INTENTION to secure a Registered Trademark. Ideally you should begin that process right away, but I'm reasonably sure immediacy is not a requirement. But, if it ever comes to a fight, first use weighs heavily as does earliest formal application for the trademark.
The true purpose of a trademark is to identify and separate your product/service/offering from those of your competitors. Think of the consumer looking at a row of shoe boxes. If I were to produce a brand labeled "Nickie" which had a curved check mark below it the legal assumption would be that I was deliberately trying to make consumers think that my shoes were Nike. I would be in violation of their trademark.
Now take that idea forward with your business. You want to create a brand image such that potential purchasers know that it's you. I believe (and I'm NOT a lawyer, yada, yada...) that you can't trademark a word, even if it's a name. You can trademark the visual expression, ie. - logo. However, I believe that you can copyright (Circle C) a name and a slogan if they are unique.