What would you recommend women do as a way to indicate genuine interest (and do so in a way that distinguishes between purely sexual interest and "I would actually like to date")?

"Initiating and escalating positive interaction" is what I use to judge if someone is interested, and what I use to indicate interest in someone.

1. Initiating: she outright proposes a future activity; its the difference between a brush-off ("I'll see you around") and interest ("I'd like to see you sometime, perhaps meet up for coffee")
2. Escalating: The proposed activity should be a little more intimate. This can be socially (from meeting at a party, she could escalate to asking him out for coffee one-on-one), or sexually (from a hug and a kiss, she could propose or initiate making out). The key here is the rate of escalation: it sets up expectations.
3. Positive interaction: The activity should offer an opportunity for good, high-quality interaction between him and her. This is the difference between proposing attending her ballroom dance class (where people are generally obliged to cycle through partners, strongly limiting face-to-face time) and proposing that she teach you ballroom dancing.

Examples of these include:

• "I'd love to meet up and chat with you later this week. Lets get coffee on Thursday afternoon?"
• "Tell me about <some story he was mentioning>, I really want to hear about it."
• "I'm <making dish, creating artwork, doing hobby>, and I would like you to <verb> it with me."

The scary part of using these is that they are clear markers of interest, and they require you to run the risk of rejection. The good part is that you can use them to weed out those only looking to hook up by controlling how quickly you escalate.