Even though is a stronger form of although. Even though I was`really tired,i could not sleep.

You can think of it in the same way as "Inspite of" An example of this could be. I look good for my age even though I've had a hard life. Or you could change it I look good for my age inspite of my hard life. Hope this helps

Eventhough is almost the same with Although,despite, and the others, however, Eventhough has a more Empathic connotation, meaning more polite, this word can be used to connect clauses. the first clause or sentence that comes after or before it should have a different conditions eg. I left him, Eventhough he still loves me or I decided to leave Eventhough it's still raining outside. Eventhough I knew she wouldn't pay me, I still lend her some.,.,,

http://www.wordwebonline.com/en/EVENTHOUGH