Dear…
I was in the __(name location)__ area __(last week/yesterday/the other day/etc.)__ and dropped in to see you. Regrettably I missed you, but I left behind __(some information/my business card/etc.)__ for you. Based on your type of business, I am confident that __(Name of organization)__ can offer sound and cost effective solutions to meet your __(type of needs)__ needs.
I hope you have had a chance to look over that __(material/proposal/information/etc.)__ I left for you. If it fits into your schedule, I would like to drop in again next week to share some thoughts with you that I had on __(briefly explain what you can do for them)__. I would be delighted to be given an opportunity to introduce our __(type of products/services)__ to you.
Please feel free to call me at __(phone number)__ to arrange a meeting. Otherwise, I’ll see you when I drop by again next week.
Best regards,