The other guys nearby won't think you are so intimidating. Now, before you get upset, let me just say that there is absolutely nothing wrong with an opinionated woman. I think it's time we stop thinking of the label "intimidating" as a bad thing.
To become even more approachable, consider the subtle messages you're sending with your body language when you're out on the town.
Even something as simple making the effort to throw out a few more smiles really helps.
Break up the perceived informality and immediacy of texting. Sometimes these dudes back off if they think there are witnesses to the behavior (the equivalent of young-waitress-me saying I once had a creepy freelance client who was overly familiar in his emails and chat communications, so I invented a fake assistant & made a Gmail address for her and started CC-ing her on my responses to him – he STFU.
I finished his project as fast as I humanly could and then turned down all future work.
To be absolutely clear, you shouldn’t have to soothe the feelings of an adult professional man who is being inappropriate, especially one you are paying for a service, but sometimes I think that it’s strategically valuable to find a way to let the guy save face if you still need work out of him.