The
Aulani Villas and Views thread has maps showing the location of all the villas by view category. Many of the villas also have photos showing the views from the balconies, so you can get an idea of what you'll see from the different parts of the resort.
You can make your request right now directly to Member Services. In fact, I would advise that you not wait until you can do the Online check-in because it does not allow you to be very specific with your request. You can call Member services, but I recommend you send an email instead. Just sign in to the Members website and scroll all the way down to the bottom of the page where you'll see a "Contact Us" link. Click on the link to get a dialogue box so that you can send an email to MS. It helps if you include your reservation confirmation #, type of villa you have booked, and dates of your stay.
We just booked an Ocean View studio at Aulani for next February and I sent an email to MS requesting a villa that offers a sunset view and overlooks Aulani's Waikolohe Valley, which is the home to the main pool and lazy river. I try not to make my requests too specific, so I requested a High Floor & villa room number ending in xx72, xx78, or xx84.