Another minor point in Russian that I hesitate about is the use of the suffixes ичный vs. ический. I could be wrong, but I've noticed that, usually with abstract words or borrowings, adjectives are said with both endings, almost interchangably. The only really good example that comes to mind at the moment is реалистичный / реалистический, but I think there are many more I have come across.
A separate but related observation is that often the two suffixes create slightly different meanings. Am I right about that? For example:
экономичный - frugal, economical
экономический - economic (as in, экономический университет)
Other examples of this would be практичный / практический and гипотетичный / гипотетический. Is there any pattern to this or way to use them more correctly or do you just have to learn them on a case by case basis?