The best restaurants on property for a couple's date night, in my opinion, are Jiko, Flying Fish and bluezoo.
My advice for each of these restaurants to get the best, most intimate experience varies from restaurant to restaurant, but here it goes:
In Jiko, make sure you don't get a table at a shared bench seat. If they try to sit you in one, ask to be seated elsewhere, or tell than that you will wait for the next table or booth. It's not a crowded restaurant by any measurement, but the tables around the center wall that have a common bench on the inside are too close together. And, really, who wants to have a couple's night out where you have to share your seat with a party of eight?
In Flying Fish, either make your reservation as early as possible or as late as possible. It's a nice restaurant with great food, but there's an open kitchen a really no attempt to isolate dining room noise at all. During peak dining hours, when the place is packed, it gets pretty loud in there. If you book before the crowd arrives, or in the waning hours, you'll have a more enjoyable experience. Plus, you'll be able to hear each other, you know, if you're into that sort of thing.
In bluezoo, the ambiance is intimate, the crowd noise is manageable even at the busiest hours and the menu is great. So, my advice to maximize your experience here is to not skip the lounge. Get there an hour early for your reservation and have a couple of drinks at the bar. The bar menu might be the best on property, and the bartenders are definitely the most well trained and knowledgeable on property. Plus, the lounge has a sexy and fun vibe that gets you started off right for your meal together later on. It's a pretty awesome aesthetic appetizer.