Ha!
Well let me start by saying that I have been a curb crawler for years. Driving down the road and you see a pile on the side, stop and pick up something someone else threw away. A chair, a desk, a plant, whatever. I bet there is a large portion of people on these boards who have done the same thing.
Then I moved to Denver. Denver has an alley system, so I sometimes would cut through the alley's in route to someplace. Same thing, see a pile, pull over/ drive slow and look. Sometimes if it was a big pile, take a quick peak in the dumpster and see what else was discarded. I have found full bottles of sealed liqour, gifts galore that are just through away for one reason or another. After yard sales dutring the summer there is a ton of stuff in certain neighborhoods.
What I don't do is dig thru people's actual trash. Believe me their is a big difference between peaking in a dumpster and looking at what's on top and tearing open a trash can liner. That is a definate yuck! Although soap will aways work in getting you clean again.
I've always be thrifty, shop at goodwill, yard sale, etc and was looking at books that the library when I found " The Art and Science of Dumpster Diving" book. Checked it out and then my BF read it as well. We were hooked and deceided to get brave and try it.
Local office supply store, craft/ fabric store/ Dollar store, close out stores, vitamin places, petfood store, etc, etc. I stay far far away from compactors. Never go behind closed gates/ fences, but most dumpsters are out in the open behind an actual store. So off to the strip mall we go. We do go at night, I am still scared, don't really know why because it's not illegal and I'm not doing anything wrong, just saving stuff from a landfill. Like it does any good in a landfill when I or someone I know can use it.
We go at night and only one night a week, as honestly we live a normal life other times maybe head out about 8:30pm... kinda late, but once we get going I'm not quite so tired anymore.

Just start looking in certain dumpster behind whatever retail place we start at. We have a little route now, places that normally pay off with at least something, but their are always bad nights.
One of our biggest problem we are facing right now is that we keep bringing home stuff that we dont' need and don't know what to do with it. Two weeks ago we found a dumpster full of valentine days cards. Like actual stock for a card store. Shirnk wrapped packages of 12 cards and envelops, all kinds, For grandmother, to grandsons, to sister, for husband, for my wife, for my son, etc, etc. It was like Hallmark threw up inside the dumpster. What a waste, seriously like 40,000 card and envelops all perfect, just were not sold in time and thus tossed away.
What on earth am I going to do with all these cards! We grabbed a few, can always use the envelops as scrap paper for writing notes, offerred up the cards on freecycle and a church group took them for crafts. But still, I let the other 35,000 go off to the landfill.
Some stuff we keep, some we give to friends/ family. A lot goes to Goodwill. I take bags and bags and bags of clothing to goodwill all the time. Unfortunately, they in turn often compact a lot of the stuff directly into a dumpster. grrr...
Sometimes it's a total miss, sometimes you find nothing, but the nights you find good stuff, it's certainly a rush.
I visit a dumpster diving forum online, they are mostly sophmoric "morons" that have bad attitudes and potty mouths, but I like to see what all they find.
Don't feel bad if you can't bring yourself to do so, it certainly was a progression to me and some of my friends/ family still can't believe I would do such a thing, but then I show them my finds (brand new silcia pack still in them $152 Columbia hiking boots last summer that fit me perfect) and suddenly they are asking me to keep my eye out of "x" item because they need a new one or whatever.
Have fun, be safe.