Rather than spend time sponging inside a square or rectangle for a focal point for your card, why not just stamp a rectangle with one of Stampin' Up!'s clear blocks?
I discovered this technique while perusing my downline Kris/Paper Fairy's convention swaps. She had a gorgeous card from Veronica Inouye. So I copied the contact information and emailed. Veronica's daughter, Lorene Inouye-Salvo help me to find the creative demonstrator who first thought of the technique, Sharon Field. Happily, Sharon agreed to be featured as a technique challenge on SA. Thanks so much for sharing Sharon!
For a complete tutorial and links to a variety of creative ideas using this technique, see Sharon's post about this technique on her blog: Created by You.
What a fun and simple technique! If you try it, be sure to upload to SA, so we can all see your card...here's a link: http://www.stampinaddicts.com/forums/technique-challenges/5888-technique-challenge-64-8-10-10-clear-block-stamping.html
Here's my simple "how to":
1. Ink your Clear Block onto the color of your choice. Veronica mentioned that you can drag it across the inkpad horizontally and vertically to create a near linen look for an alternative after original inking too!
2. Place a foam pad (either what comes with the mat pack or a child's foam sheet) under your cardstock.
3. Stamp your Clear Block onto your cardstock.
4. Stamp something else (image, sentiment or both) to finish your vignette.