I've started work as freelance photographer since 6 months. I've been doing photography since 2 years but just recently after gaining much knowledge I prepared a good portfolio for architecture/interior, product, fashion photography.

I've been sending e-mails to clients with my portfolio attached. However the chances are that 1 out 10 actually reply. That's the scenario around here. E-mails aren't always the way to go.

Most of the clients I will visit are architecture firms. I'm targeting the small to medium sized firms to gain confidence in my work and set a base. 

So I listed down the clients whom I would pitch my work to and I want to know if its okay to visit them to discuss about my service without taking an appointment?

What I think is -
If I have to wait for the decision maker for long period of time I'd obviously schedule an appointment for later. That way at least I have an appointment. Without visiting I wouldn't have the chance.

Please suggest