How do I break into proposal writing ?

Hi all, new to the forum ... Dave Gates here, northern Virginia.

I've worked as a technical writer in various capacities and environments for over 15 years, with much experience working for companies contracted to government agencies.

I consider myself a very good writer with excellent command of the English language. I'm very "computer literate," and in a side business I build custom PCs. Most of my technical writing experience (beginning in 1989) has been in IT and government environments.

*However* ... despite my excellent writing skills and long experience, my knowledge of proposal writing is very limited, and I have no experience with actual proposal writing.

It seems that just about all companies want employees with experience, and previous proposal writing experience seems to be a huge "MUST." This brings me to the same old widespread problem: If they all want experienced employees, how can someone like me break into proposal writing in the first place ?

Thanks,
- Dave G.