DIY Party Planning Tip – Lining Envelopes. Parties begin with an invitation. The invitation sets the mood and tone for the party so make sure you make a good first impression! If it’s an invitation you made, had printed or even pre-printed invitations you fill in yourself, step up the presentation and impress your guests. Lining the envelope with a scrap of pretty patterned paper is a small detail that will make a memorable impression. It’s easy to do with just a few supplies!