Establishing yourself in any business when people don't know you is not an easy task. It becomes much harder when you must do so as a deck builder company. The reason is that people tend to have very specific requirements that they need met from the deck builder company that they decide to contract with.
Thus, you might want to look into how you can pitch yourself as the kind of company that people truly want to deal with.
The best thing that you can offer most new customers are free estimates and the best possible work that you have done from your portfolio in the past. It might be enough to convince some homeowners that you are the real deal and that they should give you a chance to prove yourself. Hopefully, that is the case because you truly do deserve the opportunity to showcase what you are all about.
Make sure you spread the word far and wide to gather as many clients as you possibly can in the early days of your business. You need to buildup a reputation so that others will come and check out what you are all about as well.