When I started up it was very slow, so you are lucky you have that second job as it's not easy to get work at the beginning.
My advice would be to really take your time on every job, be polite and courteous and always go the extra mile for your customers. By doing this you will get repeat work. I remember the first month I started, it was harsh. I think I got 3 jobs in the month, but from those 3 jobs, I got 2 referral jobs the next month and 1 of those customers I'm still cleaning for now nearly 8 years later.
Personally, I wouldn't waste any money on directories such as Yell, leaflets etc. Some others here may say otherwise, but for me when I was starting out these were a complete waste of money and a massive learning curve to not fall for the hype when they call and try to sell you these amazing packages which are going to increase enquiries to your business. It's mostly BS.
Get a good professional website built, focus on promoting it locally through free online business ads and slowly build up your customer base from there. Oh, and get ready to sweat - a lot. Carpet cleaning is hard work, especially if you're not used to it and depending on what machine you get (ie a starter machine) you will be lugging it up and down stairs to start with. Once your business takes off any you have more capital you will be able to invest in a machine that you can leave on the van or outside and dramatically reduce the amount of labour you have to deal with.
Hoep that helps : )