If you want to sew some sleeves, but want to spice it up a bit, try a raglan sleeve. :)
I didn't think it would work when I first tried it, but it ended up working in my favor. I probably should've read some tutorials, but couldn't find one that could work for me. See, I already had the shirt, but I wanted to convert the short sleeves to raglan sleeves.
1. Figure out where you want your raglan sleeves to begin. Use a measuring tape or something straight to mark that line with some tailor's chalk.
2. Mark that line in the back too.
3. Cut out the sleeves. You can leave the neckline binding alone (as shown) or cut it all the way through if you won't be using it in your project.
***I could've just cut it all the way through since I didn't end up using the neckline binding in my final project.***
4. Angle your fabric a bit, and place underneath your sleeve opening on the shirt. Mark around it. Don't cut yet! Leave some room for seam allowance. I usually leave around 1/2".
5. I cut an extra piece for the back part of the sleeves. Notice how the raglan sleeve is a tad bit higher on the back of the shirt?
6. See that little piece poking out on the back of the sleeves? That's what I'm referring to in Step 5.
7. Pin sleeves to the armholes (right sides of fabric touching). Sew. Ta da!