Personality tends to match the size of your writing. If you write large letters, you tend to have a large personality and you are outgoing and like attention; most celebrities have large handwriting. If you write small letters it means you are focused and concentrate. Average sized letters mean you are more well adjusted.
If your line quality is thin, it means you are very gentle and tend to avoid confrontation. A thick line means you are more aggressive and assertive, while an average line quality means you are comfortable and well suited with the way things are.
If your S is rounded, you like to please people and look for compromises. A pointy S means you like to study new things and if the S is open at the bottom it means you probably are doing something you do not want to be (such as working in an office instead of being a musician).
The direction that your handwriting slants can say something specific about you. If it slants to the right, you are generally open to the world and like to socialize, while slanting to the left means you like to work alone. If there is no slant than you are typically on the logical side.
If your letters are spaced far apart it means you are very creative and probably have an artistic flair. Letters that are very close together indicate a pragmatic person who likes to plan ahead. The typical spacing between letters is described as one half of a lower case "o" fitting between them.
The usual culprits of open or incompleted letters are lower case vowels. If you write with a lot of open letters, you might mean that you focus on the big picture rather than small details. People who always make sure to close their letters tend to be the opposite; focusing on small details and sometimes losing sight of the big picture.
Alignment is all about concentration. If your sentences start to curve up or down, regardless of if there are lines on the page or not, it means you are easily distracted and tend to lose focus on what you are doing. A straight alignment means you are focused and tend to be a responsible person.
If you do not have a loop on your L, it means you tend to feel restricted. A full loop on the L means you are more spontaneous and relaxed.
Leaving a small space in your lower case "e" loop means you are more skeptical. A full loop on the E means you are open minded and like to experience new things.