I think that sentences have quite the same meaning. You just use it in different times and add the phrase make myself clear.
There are some of examples:
make something clear to express something in such a way that it is unambiguous and easily understood He made it quite clear that he wasn't interested.
is that clear?/do I make myself clear?
used for emphasizing your authority over someone, when you are telling them to do somethingYou are not to see him again! Is that clear? or Was I clear enough?!!
Interested in Language