I was in the same position a year or so ago. Here is what I did, others may have had different experiences.
I did not, and still do not have a "portfolio" type website for showcasing what I have done. If clients ask for examples, I point them to websites that I have made. The problem is of course, what if you have not made anything that is commercial, as often is the case when starting out? I asked my family, and my friends if they knew of anything I could work on. This worked out, as I quickly picked up two projects. Furthermore, my advice is to start out small. Don't take on more than you can handle, as an early failure is going to make it harder to get started.
Another few pieces of advice I have:
Always, ALWAYS sign a contract. Make sure it outlines what you and your client has agreed on. This has saved me many many times. When the client starts asking for features not in the contract, decide whether or not you can or have time to implement them. This goes back to my earlier point, do not take on more than you can handle, this will only disappoint your client.
Get feedback from the client constantly. If you ask the client what he or she thinks every time you add a feature, they will feel involved and you are less likely to have to things over again.
I would not register a LLC until you actually get rolling. You might even want to offer your services to family and friends for free or at a very discounted price. Once you get your name out there, decide whether you want to make a career out of it and then start planning to form a company. Running a company just adds more work.
Those are my tips for you, hope they help.