Stems
When a note is below the middle line its stem goes up. When a note is above OR ON the middle line its stem goes down.
Note that the stems are an otave in length. The fourth note, E5, touches the bottom line, which defines E3.
Beams
Beaming helps clarify the meter, and, when done correctly, makes reading music a lot easier. We beam eighth notes together based on the beats.
Note the difference between measures 2 and 3. There are three quarter note beats in measure 2, while there are two dotted quarter note beats in measure 3. In, you have multiple beaming options, but do not beam across the half-way point.
Beaming can affect stem direction. Follow the direction of the note farthest from the middle line. If they are the same visual distance, stem down.
When you have short beam for a sixteenth note, this beam stays inside the larger beam.
Accidentals
When adding accidentals to notes, make sure they precede the note rather than follow it. For chords, make sure that your accidentals are not stacked on top of one another. They should be staggered so you can read them easily.
Seconds
To notate a second that shares a stem, the lower note is on the left and the upper note on the right.
Dots and Flags
Dots always go to the right of the notehead. If the note is in a space, the dot is in the same space. If the note is on a line, the dot is in the space above the line.
Flags always go the right of the stem they are attached to.
Slurs and Ties
A slur connects two different notes together, and tells us to phrase these notes together (in one bow stroke, without tonguing, full value, without separation).
A tie connects two of the same noteheads, which means to play one pitch that has their combined length. The following example has two slurs and one tie.