It is really personal preferences--some of us are snuggly and physical, some more reserved. And Gr8gyn's advice about the "Do you consider yourself physically affectionate" is a great screening tool

But in the absence of that, a few things might be safe from a female perspective:

• If she's old school like me, a hand shake at the greet, at the very least. Handshakes don't have to be cold or businesslike--mixed with a big smile and a loose arm, and perhaps the other hand coming up to cover the handshake...is more personal.
• If that didn't feel right to initiate, a very soft hand at the middle to low back (just below the ribs, and definitely in the center) as you turn toward your dinner table or car or walk her out her door. Feeling how she responds to that might tell you alot about what might be okay later on (hand hold, etc...let's not get too racy!)
• Letting her initiate works well if she's fairly straightforward, but if she's shy too you may need to initiate a touch to the upper arm at the table, etc. If she does it first, you're being given permission to respond in kind.
• Sometimes, just plain old physical proximity tells you a lot. If, after some time talking, you lean in; or walk with her and walk a bit closer, you may find she's leaning to you, too. Do NOT miss this chance to take her hand, k?
• If all else fails, and you're walking somewhere, you might find an exaggerated move, like a big smile with a little bow and putting your arm with elbow bent to offer her the chance to take your arm gives her permission to touch you.

If none of these work, and you're the touchy person you indicate you are...I got this feeling she's not.

g'luck!