When we moved to the LA area, I scoured Craigslist and Zillow. I emailed some, but called more (many people around here leave their phone only). We got something around 7/30 to do showings...others never picked up, were already rented, etc. So my advice: try calling when you can and if you email, make sure to sound real and serious; proper grammar, friendly and personal tone. We were also recommended a realtor who worked with rentals by a friend, and that's how we ended up in the awesome place we have. She was able to show it to us before it went up on the mainstream sites (showed it Saturday, we signed Sunday, phones were ringing off the hook Monday, we moved in Tuesday). And she was paid by commission on the deal, by the landlord, basically. No $$ out of our pocket!
We did also find one the CL/Zillow route, though. It was smaller, slightly more expensive, and worse located, but perfectly suitable.
On that subject, are your expectations realistic? Our requirements were limited to: >500SF, >1BR, some kitchen counterspace, full size stove/oven (this was an issue), grounded electrical-3 prong outlets (this was an issue... >_<) AC and parking was a huge plus but actually present everywhere we saw so not really a factor. We were willing to forgo dishwasher, fridge (often occupant-provided here, it's weird), laundry, outdoor space, etc. Basically cut it down to our bare minimum requirements.
What's wrong with the place you are in?