Outside: Always either bright and cloudy, or a well-lit night. The sky is almost always a solid white or varying shades of deep/dark blues without any stars or clouds. Nighttime in cities means late at night with ample street-lighting. Occasionally a dream will start at twilight and progress into a darker night. Nighttime outside of cities brings indirect light from undetermined sources. It never rains on me. If it rains, I don't get wet.
Inside: During the day, indirectly sunlit. In large buildings, usually bright florescent lighting, well dispersed like at SPL's central branch in the stacks. During the night, light ranges from the same level of dark colors, but ample lighting as outside, to very dimly lit rooms. Dimly lit rooms are creepy. Light switches don't work, but sometimes I can will more light into a room. Once I threw a gorgeous pattern of light onto a ceiling that resembled the light and shadow patterns one might get from an intricate lamp or chandelier. Haunted houses have different lighting in every area.
Bathrooms: Never functional. Often giant, open rooms full of hundreds of different toilets, each with their own problems. Sometimes just a few stalls without toilets. Filth, overflowing water, dim lighting, mustard yellows, and hauntedness abounds. I used to get trapped in these, but more often now I find someone to lead me out of them, or just do a quick pass-through on my own.
Mirrors: Always functional, sometimes more than functional, never doorways, but occasionally threaten vortexes.
Cities: Almost always the same city, but different neighborhoods. Buses rarely show up if I'm at a bus stop, but sometimes I'm on a bus. Cars rarely exist. People on motorcycles sometimes give me a ride to somewhere new. Once I was in "France" and that city was distinctly different architecturally - colors were different too - a darker gray sky, and the buildings were sand-colored rather than black and metal. Very few people on the streets, though I sometimes have an entourage.
People from real life: Often manifest as two distinct people. Upon waking, it will take me a while to realize that they were both the same person, just different manifestations. Once recently, this tipped me off that I was dreaming, when two very similar manifestations of a friend entered an elevator with me.
Elevators: Rarely function properly, often take me to the wrong floor, or I get stuck in them; often end dreams. I prefer the stairs.
Stairs: Often emergency-exit style stairwells. If I'm running, I can hold the banister and fly around turns. This is fun, and speeds me up. In old mansions, there are always at least 2 stairwells. At least one of them will be falling apart in places, and at least one will be particularly more haunted than the others, but often more solid.