Glue and finish nails are probably easiest. The nails aren't really necessary, but will help if you're short on clamps.

Judging from the date on your post, you have already attached the face to the cabinet but there is an alternative to nails. Get a Kregg Jig at Lowes or Home Depot. It's a nifty gadget that allows you to drill a slanted countersink hole from the inside wall of your cabinet. It's basically a clean way to "toenail" a screw. Drill several of these countersink screw holes and then screw your cabinet face on from the inside. You can putty the countersink holes on the inside of your cabinet if you wish.

Glue and your choice of alignment or auxiliary fasteners. I typically use glue and a few biscuits (for alignment) and clamps. I may try pocket screws on my next cabinetry project where they are appropriate and do-able...they eliminate clamping beyond a few minutes of time.