In this instructable, I will describe how you can make a t-shirt for your dog out of an old human-sized tee.
Step 1: Materials
The first thing you'll need to do is gather your materials. You will need the following:
pair of scissors
sewing tape measure
Sharpie for marking cuts (not pictured)
needle and thread (optional)
sew-on velcro (optional)
When choosing a t-shirt, it is best to pick one that has a neck roughly the same size as your dog's. That way, you won't have to deal with cutting the neck down to fit or worry about cutting off Fido's air supply.
Step 2: Measure!
Using your tape measure, get the following measurements:
around the dog's middle (middle of chest is best)
distance from neck to tail (along the back)
distance from neck to mid-stomach
shoulder to elbow (to determine sleeve length)
Step 3: Cut #1
Decide which side of the shirt you want showing and turn that face up on your cutting surface. Your first cut will be from the neck of the shirt to the length of the dog from neck to tail. Make your mark (and make sure you leave yourself an extra 1/4 inch or so for a hem) and cut across the bottom of the shirt.
Step 4: Cut #2
Next, you'll want to cut away the extra fabric from the sides so the shirt will fit right. To do this, mark out a section at the bottom of the shirt that is half as long as the distance around Fido's middle. Make sure that this section is centered. Then start drawing a line from your marks upward. When you get near the armpit area, use a French curve or plate or some other rounded edge to continue the line around the armpit and mark off about half of the sleeve to be cut. (If your dog has particularly thick forelegs, you may need to save more of the sleeve.) Once the marks are made, just cut along the lines. Don't forget to leave room for a hem.