Just try adding your fieldtype to a Safecracker field and see whether you have any problems. Look for php errors, and javascript console errors.
Generally, the main issues you will run into will either be loading static css/js files which aren't accessible outside the control panel, or calling php functions which aren't accessible outside the control panel.
For example, a fieldtype I added Safecracker support to was making an AJAX call to a method on my mcp file. I had to change this to a regular EE action so that it could be called from outside the control panel.
One final thing to watch for is making sure your fieldtype looks alright with a white/different color background.