In short, the answer is a big YES. It is absolutely necessary that you back up your pitches with an online and offline presence that matches who you say you are and what you offer. At a minimum, I suggest you create the following:
An authoritative website
This is a website that establishes your credibility as an expert in your field. It should include testimonials from your clients, a client list, your biography with a focus on what makes you an authority in the field of social media, a list of the services you offer and any press coverage you have received. If you've written any articles, you should, at a minimum, provide links to them. Lastly, I’d strongly consider adding a blog to your website and updating it regularly so potential clients can check out just how knowledgeable you are.
Real-world business cards
While there is no need at this point to get any fancy stationery designed, you do need a business card to hand out when you meet prospective clients in person. As for a logo, I would not spend any money on a logo mark -- which is an image -- but stick with a typographical treatment of your business name.
Stellar social media profiles
It sounds obvious, I know, but if you are promoting yourself as a social media expert, your own social media sites need to be up to snuff. A few basics: Make sure your social media sites match the branding of your website in look, feel, design, colors and message. In addition, make sure your profiles are 100 percent up-to-date and complete.
If you implement the above, the next time you pitch you will be able to back it up with online and marketing materials that make you look like a serious pro.