The difference lies in the use. You may want to make sure you are on time. You may want to make sure that you are on time. You may want to make sure of being on time. You may want to make sure of your arrival on time. You may want to make sure about being on time. Hence, we can know that "make sure" often precedes a subject or 'that' of a clause to follow while "make sure of " and "make sure about" follows a verbal noun (that is a noun derived from a verb) or an object. Of the two sentences you have given above 1) is correct.You can also alternatively use "make sure about" in that sentence.

1st one is correct. make sure that you do all your homework before going out. make sure of doing all your homework before going out.

1

You may want to make sure of three things. - is correct.