I'm a Rabbi and have had non-Jews work for me in tha past.
First of all, know that in general we will totally understand and 'get' that our co-/workers aren't of our religion and it's totally ok. For example, I play ice hockey, and once played against a team that had a girl on it. After the game we all went to shake hands, and I was in a dilemma. She tried to shake my hand, and I had to explain that I couldn't shake her hand for religious purposes. I gave her a Japanese style bow and took off my helmet for her instead.
But I understand that you don't want to get into awkward situations. Here's what I'd advise:
1 - No touching of the opposite gender. Not even gently at the sleeve or on the shoulder to get their attention. We are extremely modest and only touch our wives and close relatives (if you were ever a teller in a kosher store, you'd notice that you'll have to drop the coins into a religious Jew's hand).
2 - Don't post pictures of you/your family/your friends in clothes that are immodest around the office or as your computer background. You will gain a LOT of respect for posting pictures of you with your friends, dressed very modestly.
3 - Keep your own food away from their food, so they don't get worried about eating non-Kosher. If you ever feel pressured to bring an office gift or something like that, go with flowers or a bottle of wine. Make sure it is Kosher and VERY IMPORTANT: Mevushal (usually that word is on the back in English letters but you can google which wines are Mevushal). Don't go with chocolate since unless a fellow orthodox Jew shops with you.
4 - Try to get used to not saying "Jesus", since it offends some Orthodox Jews.
5 - When chatting with someone of the opposite gender, try to never be alone in the room (i.e. just the two of you). Leave a door open. This was advice given to me before I went out to Russia to be a Rabbi, and I found it to be very practical advice.
All in all, you shouldn't worry about it. Orthodox Jews are generally very nice and kind people, and should a misunderstanding happen, be direct with them and ask them what you did wrong. If you ever have any questions about these things, feel free to email me.
