Force touch is an interesting interaction, but when I bought my iPhone 6S to play with it I ended up force touching all applications and UI elements to check if they support force touch. Discoverability of the force touch is so poor now, seems that there are no established design patterns yet, when it comes to it.
What do you think are the best solution to indicate force touch in your apps?
Apple has published couple of guidelines. With regards to 3D Touch, they seem to be taking hands-off approach on the discoverability because its usage patterns can be quite varied.
Indication of peek availability
With a light press, surrounding content blurs to tell the user a preview of additional content—the peek—is available.
Interactive Elements Invite Touch
To signal interactivity, the built-in apps use a variety of cues, including response to pressure, color, location, context, and meaningful icons and labels. Users rarely need additional decorations to show them that an onscreen element is interactive or to suggest what it does.
On a device that supports 3D Touch, the background blur that users see when they press on a Home screen icon signals that more functionality is available
