SV has a culture of getting to investors through trusted sources. Email a few of their portfolio companies that are relevant (but not competitive) with your business, ask to buy them lunch and chat for a bit, then ask for an intro at the end of the meeting if it goes well.

From the investor's perspective this a) filters out people with no conviction, b) filters out spray and pray-style emails, c) helps them manage hundreds of emails they receive every day.