Do Your Research on Visa Requirements
Make sure you do your research on your destinations visa requirements! It’d be a real bahumbug if you were to show up empty handed, lord knows what you’d have to go through. Wikipedia has put together a handy-dandy “chart” if you will, listing all the requirements for US Citizens. You can find it here.
If you’re still not sure, call the embassy! They’ll be able to give you the 411 on requirements and payments. Luckily, I remembered to check the requirements for my trip in May to Qatar. I knew they were Visa Upon Arrival, but what I didn’t know was that I have to provide two passport size photos as well as $160 processing fee! It would have sucked if I had shown up without them.