Deposits??? Yes or No??

Yes.  Always get a deopsit, and make sure that you state that it is non-refundable.  I do mainly wedding cakes so my price point and average order are probably more than what you deal with, but I require all orders under $300 to be paid in full to book and orders over $300 required a $200 deposit and the balance to be paid 4 weeks before the event.  Any orders made with less than 4 weeks notice are paid in full to order.  On average cake orders are $600 and up so that works for me.  Many people require a 50% deposit (again non-refundable) and the balance due anywhere from 1 - 4 weeks before the event.  It all depends on what you are comfortable with. 

Take in consideration your average order amount and calculate something from there.

ALWAYS either get a deposit or payment in full when confirming an order.  I don't consider a job booked until I get payment of some sort.  I find that if I don't get a deposit, there are some people out there who may cancel at the last moment - then all of that time you spent (not to mention product) has been wasted.  For wedding cakes or more expensive custom cakes booked far in advance, I require a 50% deposit with the balance due 30 days before the event.  If I get a birthday cake order within a few weeks of the event, I get payment in full.  

When I first started out, I didn't take credit cards.  The deposit/immediate payment thing got a bit tricky, especially if someone only ordered something a few days in advance.  Now I use a Square card reader which I plug into my phone or iPad.  I can immediately run my customer's credit cards and know that the payment is accepted (while they're still on the phone).  There is a charge - I believe it's around 3%, but the peace of mind is totally worth it.

In time you'll start to be able to weed out the ones who are truly interested in purchasing a cake and those who aren't.  Good luck to you!