So as a "consultant" you should go in to your initial meeting with the intention of better understanding their current marketing setup, processes, etc. Once you've gotten that info, you can then package together a proposal which should outline a plan of attack, which you've successfully implemented in the past. Assuming they've agreed, you then implement and deliver!
I have many clients who have seen great results in the last few years because of a plan of attack I put together, not based on theory, but based on case studies, tests, etc.
Whether it's a client needing a responsive site, or a strategic email marketing campaign setup/tweaked, you've got to know your client needs and how you're going to tie in all systems to make it a success, you can't just guess, and hope it'll work. (That may work, but it's a huge risk...)
Bottom line, if you don't know 100% the web design or marketing service/systems you're selling and you haven't tested them successfully, then you're not in a position to sell yet, IMO. If you want to build a successful business that has longevity, then I would strongly recommend you are well prepared before you go in the trenches and start selling to local businesses.