Customs. An Issue?

I really never thought that I would ever have to worry about customs, but this weekend I find myself learning about customs and international shipments. I never though that I would ever have to concern myself about anything like this, but I find myself in a situation that I thought of too late and may change the way I do business...
you see, I have found myself in an interesting position (not at all unique, but new to me) I have gotten three international requests for orders and two confirmed, just this week. the most international anything I've ever had before was to email a pattern to Canada.
after finishing and listing one of these confirmed orders I realized that customs might become an issue. I'm just not getting the answers I need from the USPS website and I will therefore stress out about it until morning.

One order will be going to Great Britain, the other to Australia. mainly I took the order for Australia just so I could be all 'I made something and now it lives in Australia'
from what I am seeing so far, I think I might not have to worry about it at all because of the size of the package but until I am certain I find myself stuck freaking out a little


however, if customs does not become an issue, since most of what I can ship I can fit in a little bubble wrap mailer and that might be okay... I might just change all my orders to include shipping internationally.

well, maybe....