Turn your pre-made slipcover inside out and place it on your couch or chair. Tuck and fit the slipcover as best you can.
Look for any excess fabric on your slipcover that may give your furniture a sloppy appearance. If it is too loose around the arms, for example, pin the two sides of excess fabric together by the seam. Always try to stay close to the seam to give your slipcover a custom appearance.
Pay special attention to the section of the slipcover that grazes the floor, also known as the hem. If it is too long, pin it up so that it hits just at the floor or slightly above.
Mark any sections your have pinned with a fabric marker in case any pins fall out. Remove the slipcover from the furniture slowly, making sure all the pins remain in the fabric.
Sew all of the seam lines and the hem according to your pins and marks. This will give the slipcover a taught, polished appearance.
Add decorative embellishments to your newly-fitted slipcover. If your slipcover has piping around the edges, choose a complementary color and paint it using fabric paint. If there isn't any piping, sew colorful cording onto the edges and seams. This will give that overstuffed chair or couch a more structured appearance. Attach some lacy fringe to the bottom on the hem of your slipcover for a festive look. Try adding some covered buttons, beads or rhinestones up the arms and around the edges. This is your chance to make the slipcover fit in perfectly with your decor, so choose colors that are already represented in the room.
Iron your slipcover thoroughly before placing it onto the couch. Your couch will look elegant and inviting with neatly pressed fabric.