While it’s really easy to start a consulting business, you can’t be mediocre at what you do and expect to get lots of customers or repeat business. Trying to do the aforementioned just isn’t honest when people are paying you money.
I don’t recommend you put a ‘Hire Me” on your blog until you feel completely confident that you can offer what your service will advertise.
For example, I read a book that I found particularly helpful multiple times before I started my Email Life Coaching service because I knew I needed to become more knowledgeable about personal-development before I could help people on a higher level.