The capacitive touch pads on the Crickit have large holes so its easy to connect alligator/croc clips. That's how we recommend you attach to them. The "small" size clips work best:
You can also use copper foil tape. Note that if you get foil with conductive adhesive, you can tape the foil right onto the Crickit pads. Otherwise you'll need to use alligator clips to grab onto the copper.
You can use other conductive materials like paints! Either drip the paint into the pad itself and let it harden, or use alligator clips to connect from one pad to a paper with conductive paint on it.
Remember: If you absolutely need more capacitive touch pins, Signal #1, #2, #3, #4 are four more capacitive touch inputs.