Yeah, I know, I never do this kind of stuff. Especially not snail mail themed stuff. Usually I just complain about how difficult it is to send snail mail, or rant about how weird the lady at the post office was. Not this time though. This post was actually requested by Cora from Tea Party Princess so... I'm going to be serious for once, or at least try to, and show you how I make envelopes for my snail mail.
You don't need all that much: scissors, a pencil, a ruler, glue and a piece of paper to turn into an envelope. If your heart is strong enough and you think you'll be able to live with the guilt, you can use old atlas pages or even pages from an old book that has no chance at a future anymore as paper for your envelope. It'll look cool, but it breaks my bookworm heart a little to do so. That's why I took an illustrated page from an outdated magazine as base this time.

Now you're going to need something like a template. You can make one yourself or take mine as base. Print the image, resize and that kind of stuff. Mine's usually 16,3x11,2 centimeters, but whatever floats your boat is great. Put the template on the paper, trace the outline and cut it out. Easy as that.

Now turn your paper around so you won't deface it with ugly folding lines. You do need those folding lines, but it's better to put those on the side where no one will get to see them. Time to pick up the ruler and make the ugly side of the paper look like this.

Next step: trace the folding lines with scissors. Best to keep the ruler next to the scissors so you get a straight line that actually is straight. Also reduces the chances of you almost cutting off your fingers (I speak from experience here). Probably stating the obvious here, but: trace the lines, don't actually cut then, because that'll make your soon-to-be envelope fall apart.
After tracing the lines you can start folding. It'll start looking like this:

Now put some glue on the flaps on the side. Quickly put the envelope together and TA-DA! Your envelope is ready!


One last thing: most envelopes made like this aren't practical in terms of address readability, so I usually stick a piece of white paper to the front as a label. Now your snail mail is ready to be sent. Okay, yours is. I couldn't find white paper for the label, but you get the idea!