Here are some rules the beaming of notes.
The fractional beam should point toward the note of which they are a fraction
Consider the following example. The direction of the beam can influence the interpretation of the grouping. The second rhythm suggests the grouping is as in the third rhythm.
It is helpful to extend beams so that they start at the beginning of the beat. This aids the musician so that they can see where each beat begins more clearly. This is only done on ryhtmically complex music
Beams should extend over rests in rhythmic notation.
Beams should bridge rests appearing within a beam unit
Another way of using exteneded beaming is to use stemlets as well. According to Stone, this gives an even clearer view of the notation being used
For rules about beam angles click here.