First of all if you don't know much basic music theory e.g chord construction, then consider getting a teacher or pick up a book if you don't want to pay for a teacher.
Secondly, scales, practice, practice, practice! Play them until you don't have to think about them! And don't just only play them going down across the strings, play them on one string, then the next, and so on, until you know them inside out across all strings. If you know your scales (as simple as they may be) you'll find yourself relating the notes to one another easier.