So Christie's post about her amazing pinata demonstrates how to paper mache. Personally, minus those two or three times in summer camp for various what nots, I have never paper mached. I know, call me crazy! I think it's amazing and well, her pinata looks great, but I have never really required paper mache for a project.
However, decoupaging IS something I partake in quite often. Boxes, letters, more boxes, more letters...I have Modge Podge on over half of my winter sweaters (making J & C boxes a gazillion years ago). Currently I have Modge Podge on my nice wood dining room table. Only because each time I put down paper, my letters (which is what you will get to see today) kept sticking to the paper and then getting the paper print imprinted on them. Therefore, I went with the table (testing that the glue, with careful scrubbing with a soft paper towel and water) would come clean.
Let's begin with the basics of decoupage. First, you need some kind of object to decoupage. I used a chipboard letter (well, lots of letters, but whatever). If I ever can find it online, I'll post a link.
Oh...I should put a list of items you will need first:
Modge Podge (use the kind you feel comfie with...I usually just use the Classic kind)
Object to be decoupaged (box, letters, frame, canvas, etc)
Paper or fabric (I love ordering paper from Paper Source)
Exacto knife (No. 1) with a No. 11 blade
Extra No. 11 blades
Metal straight edge
After you choose your object, you need to choose something to cover it in. You can use fabric or paper. I used paper because fabric has a tendency to get saturated with the liquid part of the glue and turns an odd color. But sometimes it does fine, you just have to experiment. Kara did a fairly amazing job decoupaging fabric onto a dresser. It's a great project in general for a furniture facelift.
In truth, you can use almost any kind of paper. I've used handcrafted paper, printed paper from an inkjet (make sure it dries well! It will still have a tendency to bleed though), cardstock, stickers...pretty much anything. Cardstock is a little harder to work with if you need to bend something around an edge, but you can do a pretty good job if you cut it. On this particular project, I just found different papers I liked ranging from cardstock to handmade paper.
Your first step would be to brush your letter with Modge Podge (make sure you have it facing the correct way if using letters - the "correct" way is reading as the letter when it faces you with the paper over it - unlike my finished, backwards "J" shown below).
I usually go ahead and brush the paper with Modge Podge also. Then, I simply place it face down and stick a heavy book on top of it and let it hang out overnight to dry.
After it has dried, I take my metal ruler and cut the excess off the paper. Because I want to fold the paper over the edges to cover the sides of the letters, I measure the average distance to cut. It turns out that the perfect distance is the width of my metal ruler. Woo!
When using letters or even boxes, it gets a little tricky when corners are concerned. We'll start with a square corner. There are several ways to do a square corner. You may just have to experiment a few times to see what works best for you. My favorite (and in my opinion, the easiest and least thought) is to cut a straight line from the corner out to the edge so that it ends up being square. Do this for ALL your corners before moving on to more gluing. After all your corners are cut, gently fold the corners how you want them to get them to be shaped. You'll probably want the corner tab you've created to be under the opposite edge.
Before gluing your corners, if you have a letter with curves or what not, you will notice that your folds may not cover the sides of the letter (or object). In order to fill in this void, you will need to cut strips of paper from your leftovers (once again, I just used the width of my metal ruler). Place this strip in the area you need to cover and measure it, cutting off any excessive ends. Go ahead and glue this strip (or many strips in some cases). After the strips dry you can continue to the next step.
After shaping your corners, you can now go ahead and apply an even layer of Modge Podge to the inside of the paper and then fold them where you want them. Try not to go overboard with your glue as too much glue means you'll be holding a corner for a while. Too little glue, however, means that you will have bubbles in your paper. Not so good as you can't exactly go back to get rid of them as this is your big moment.
So, up until now, basically all that you have accomplished is gluing your paper to your letter (box). Guess what? The easiest is yet to come: actual decoupaging.
Now, just cover your objects (over your paper) with a layer of Modge Podge. Make sure not to do every side of it as it's likely you're not going to want to sit around and hold your object while it dries. That would just be silly!
You can do another coat or two if you like (after it dries of course). I usually do two coats and that seems to do the job.
Here are my finished letters for the kids (note I used the backwards "J" for Jace's name and simply mirrored the image in Photoshop so you could see the finished product).