The sun is out, the birds are singing what a great day to get out and cold call. No one likes to cold call, but whichever profession you are in, it can be effective. I have gotten phone calls six months to a year later which lead to some of my biggest clients. Just keep trying and make contact often. Once every 1-3 months they will at least admire your dedication and when the opportunity arises you will be ready and hopefully on their mind.