Stop and think for a moment - How do you see the world around you, and how do you go about noticing it? Then comes the fun part - how do you translate that into words?
There are several levels of seeing, and remember, you can only see what is in front of your eyeballs, though peripheral vision counts too.
First would be the casual notice. If you're walking down the street, consider all that you notice and why you notice them. You see cars and fellow sidewalk walkers, and you see them primarily because they are moving. On some level you make sure their motion will not intersect with your motion. You notice those objects and people who are not in motion only in so much so you don't run into them. Now tell me, could you describe them? Guys might notice a cool car and therefor be able to describe it, and girls might notice a nice shirt, dress or perhaps hairstyle. This extra interest would be the next level of seeing. So there's this red-hot red Ferrari stuck in traffic, or this woman wearing the shortest skirt you'd ever seen just walked by, or whatever oddity comes to mind, I'm sure you can recall some. Now tell me, what do you hardly notice at all? Do you notice the sidewalk or the street? How about the buildings you're walking by? Could you tell me what shop or building was three away from the one you were headed to? How about parking meters or light poles? What other things clutter the street to your favorite coffee shop. Next time you go, pause a moment and make a list of all the things you see along the way. I'd be surprised if your list was short, and don't cheat by driving there and parking out front - it's not the same. haha
The next level of seeing would be in looking for some place, you might notice differences along the way. Lets say you drove to your home town or neighborhood for the first time in say ten years. After a lifetime of familiar this or that, differences would be glaring. New storefronts, new houses where old ones used to be, empty buildings where something favored used to be. There are different levels here to. You are looking for the familiar and finding them or not, but don't forget all the other things.
The next level, and perhaps the hardest to deal with, is the scrutiny. When you or your character stops for a moment to consider their surroundings carefully. You need to remember that you can only see what is in front of your eyes, and only what is in view. It's tempting to map out the immediate area, and that's fine for use somewhere along the line, but if your character hasn't seen first hand, or heard of some portion on that map, he can't know of it. There might be twenty men hung from the branches of the trees in a picturesque orchard, but if they aren't visible from the house, unless your character takes a stroll down into that orchard or catches a whiff of death and decay on the wind, he's not going to know anything is amiss in it's depths.
Now that I've got you thinking about what and how you see, now comes the fun part - putting it into words. They say a picture is worth a thousand words and that's probably true. Take that stroll to the coffee shop, by the time you devoted say one to five words to each thing you noticed along your walk, you might have near a thousand by the time you reached your destination. And the trip to your home town, since the view and the details are different, still you'd likely have roughly a thousand words chocked up from the time you entered the city limits to the time you reached your old house. Even the scrutiny is the same; how many words would it take to describe the view from your front door?
Descriptions are difficult to handle, especially if you want to avoid the information dump. However, thought can go a long way toward accomplishing that. Small-talk with a friend can too. Be careful with this; endless smalltalk can have your audience walking away bored. Trickle you descriptions in one step at a time. Talk about that one thing only if and when it catches our attention, only if it moves, or if we need to avoid it. Stop to scrutinize your environment only when it applies directly to your plot or to distract you from it for a much needed moment of escape.
Learn to consider your story as a tapestry. There's the warp, the design and color, which would be the main point of your story. Then there is the weft of the tapestry - all the threads that hold the warp together, that would be the environment, the background, all the little details that gives your story its life and reality.