When it comes to photographic technique the options are endless, even with professional speciality areas like real estate photography.
It's all about choices. This fact applies for working agents who do their own photography and working photography professionals. Modern digital cameras and fancy software are modern luxuries in this arena, but there is no substitute for experience and solid technique. Shortcuts and automation can save time but consistent results always seems to suffer.
Cameras: I use the latest modern full frame digital Canon SLRs.
Lenses: I am a gear junky and own around 18 lenses. Most of my real estate work is done with three modern Canon "L" series zoom and Canon TSE (Tilt-Shift) prime lenses.
Tripod: I always use a tripod. This greatly improves image quality while ensuring the best composition. The tripod helps eliminate unwanted fisheye distortion. I take care to make sure that horizontal and vertical lines are straight and distortion free as much as possible.
Lighting: The trend these days is to not use any added lighting at all. Some photographers just rely on HDR (high dynamic range) techniques. Here the photographer quickly captures the same scene using a wide range of different exposure (over and under) settings and then uses automated software to merge them all together. This sort of solves the exposure challenges but can present a very false, plastic looking image. I prefer to light the rooms to lift the interior exposure value to the natural window light. I use about four strobes, mostly bounced off the ceilings which also helps maintain a more natural looking color temperature. Bounced lighting makes the rooms look more cheerful. HDR rooms often have dark, heavy looking ceilings. Contrast and colors often look garish with way too much saturation. Window light looks like it was produced from kid's Playdough.
Computer technique: I use a 30" professional calibrated display and Adobe Photoshop. I always use RAW to capture the images. I then use Adobe Raw software title to tweak the color and exposure settings before bringing the files into Photoshop. I often create two or three different exposure instances of the same file and then use careful custom masking techniques to control shadow and highlight values. This is way more TIME CONSUMING than the instant HDR technique that may photographers deploy. I think the extra effort is worth it. Once mastered these Photoshop masking techniques can be performed quite efficiently, it just takes experience. I then save all the edited files as large uncompressed Tiffs. I then make two Jpeg versions, one for the web and one for any printed brochures that may follow.
The average listing shoot produces about 14-20 images. Showing 36 images is not worth the extra hassle as prospective buyers will not spend that much time viewing one gallery listing before moving on to the next. If you have not attracted the buyer with the first dozen or so images then showing another 20 images is not going to make that much of a real difference.