I'm assuming you're meaning the restaurant if you're seeing that available.
If you're meaning the Lounge, you need to plan on putting it as far into your trip as possible - and realize that it's predominately parties of 2 - apparently there may be one table for 4.
The times we haven't been able to get an ADR we have just done a walk up and have never waited more than 10 - 15 minutes at lunchtime, (and I hate to wait.)
That's just our experience and I'm prepared to hear I made it all up.
Another tip for Landry's is to buy the discounted gift cards at Costco. You can do this online. $100 of cards for $80. They are good at Y&Y or any Landry's location. If you are a WDW passholder they offer a 10% discount off your food. I don't think Y&Y accepts the AAA or AARP discount like other Landry's locations. You probably can't earn points with the Landry's Select on the same check as you get a discount. Though YMMV as we have had some servers do both. The good thing about the 10% discount is that it is instant, no need to accumulate points on Landry's Select. Combine that discount with the gift cards effectively gets you 30% off.
I should add, you can't earn Landry's Select points when you pay with a gift card. So you can't really tripple dip on the discounts other than using the gift cards with Passholder.
