I always respond to messages that are polite, specific, and include all relevant screening info.
This means, include:
-where you found her ad. -when you would like to meet. -for how long. -verification membership (i.e. - here's my Date-Check, P411, RS2K information) or screening info (I work in the bio-tech industry. If you respond, I'll be happy to send information for occ. verification. You can also contact Lola Hot Stuff and Jemini Jools - links here - as references). - your contact info (cell number - don't call me or text between y & z). - a bit of extra info about you.
If she doesn't respond in 30 min - 1 hr, call or text her and say you sent an email and would like to meet up that night.