If you have access to a word processor even for a short time, design a letterhead with your name, address and phone, which can be used for both resumes and letters. Page designers for newspapers and magazines and advertisements know the value of white space, and many hours and dollars have been spent combing the latest theories of psychology and communication and attention spans. What it boils down to is simply this - white space is pleasing to the eye. Use as much as you can. Margins should be uniform, double-space between items.
Justified type looks better in most cases than ragged right margins.
Many resumes have section headers on the left, with sub points indented in a block to the headers' right. This technique provides quite a bit of white space. Define each section clearly. 12 point type is better for most typefaces. There are many typefaces available, but stay away from those that are not easy to ready, or that look less formal.