Ahh, a hard thing to explain without pictures. See, the english "R" is pronounced like dragging your tongue on your palate from back to front, which makes a "middle" 'R' (not hard and not soft). Now, the "hard" 'R' in spanish and normal "R" in finnish is making vibrate your palate with your tongue, as if it were a earth-quake. (I recommend you search in youtube videos and try to learn good it). The soft "R" in spanish like the "R" in english, but, instead of moving your tongue from back to front, you do it backward.

I don't know if this is going to help you, since I don't really know how to explain it in words, but here's an useful topic, ”Tricks to trill the R”, on UniLang: http://www.unilang.org/viewtopic.php?t=9318 Also, you might want to go to http://www.forvo.com/languages and listen to the pronunciation of Spanish and Finnish words that have the letter R. It will help you to understand how it's really supposed to sound like when put into context.

pronounce "R" in Spanish = '' ere or erre ''