The first thing you need to do is to look for the show formatting symbol
see
http://office.microsoft.com/en-ca/word-help/show-or-hide-formatting-marks-HP005189641.aspx
Click on that icon and see if you have been adding soft or hard "returns".
I have called them soft or hard "returns" because this is the end of line character that is added to your document when you press the RETURN / ENTER key.
If you have lots of (either soft returns => you press SHIFT + ENTER together) hard returns you can delete these to get the lines to go closer together.
Otherwise you may format text be selecting what you want and (using the drop down menu) select FORMAT => PARAGRAPH and then choose the number of points (pts) before or after the paragraph.
You get a new "paragraph" every time you hit RETURN / ENTER.
Does this help?