The key to using an extractor and not leaving a lot of water in the fabric you're extracting is to do quality dry passes where you let the vacuum suck or extract the water and/or cleaning solution out.
To do this you cannot move the wand quickly over the surface, you must move it slowly over the surface to provide ample time for the water to travel through the fabric, upward and into the wand.
In all my classes we use the clear, plastic wands instead of the stainless steel wands because they let you see,
The dirty water being extracted and when the dirt has been removed
The clean, rinse water being extracted and when the all the water has been removed.
Then you place an air mover inside the car and roll the windows up so that there's an inch or two air gap for air to flow in and out of the car for evaporation to take place.
I have some really great pictures of the cleaning, rinsing and then dry extraction process taking place from last weekend's class and even the class before when we extracted the Airport Taxi Van but it's always just a "time factor" to go through the photos and then do all the work it takes to get them inserted, not merely "attached".
Here's some pictures from another class showing the process and the added benefit of using a clear, plastic wand instead of a solid stainless steel wand.
Pictures & Comments from May 5th & 6th Detailing Boot Camp
Here's Tim using the Aztec Hotrod...
You can easily see the dirt being extracted out of the upholstery...
Making a follow-up pass shows the dirt has been removed...
After all the clean, rinse water is extracted you can visually tell because you won't see any water being lifted out of the fabric. This is your sign to move on...