Don't wait until the last moment and rush around trying to find everytning. You can easily get distracted. Don't let anyone you don't know handle or watch your things. If someone approaches you for money or wants to sell you something or offers to give you help, just say no and keep your eyes open. They may be genuine but it is best to play it safe.
Most pickpockets work in pairs, one to distract and one to extract.
If you need help, you pick out the person and the place, not the other way around. While you are at Coca Cola, or any other bus station, keep your eyes on your things all the way up until the bus leaves. If at all possible, travel with only a carryon bag and store it above you in the baggage rack. The Gringo zone is centered around Parque Morizon and the bars, restaurants and hotels. Actually, you should be careful at all of San Jose's parks, even during the day.