Except for the tricky arc of stem (called a hook, in the 'f'), 'f' is basically an 'i' or 'l' with a cross stroke. The cross stroke is an important part of the 'f' since it's one of the most distinctive parts of the letter, and also because it will be reused in 't' and many special characters.
Components of a lowercase 'f' |
The hook can be roughly outlined with two circles. However, it's not perfect. The hook curves away from the outer circle at the terminal, and the inner circle is more of a distorted oval that pushes up to create the hook's hairline.
Left to right: Garamond, Minion Pro, and Palatino. |
At this point we just have to draw the cross stroke and worry about the balance and proportions of the letter.
Because the 'f' has an right overhang, the right side of the foot serif needs to be extended a bit to keep the letter from "falling over".
So applying this correction to our 'f' :
Now for the cross stroke. It is important to note that the cross stroke is not the same length as the foot serif, nor does it extend all the way out to the end of the terminal. It usually extends to somewhere between the two. The cross stroke does, however, generally align with the left end of the foot serif. It also tends to taper off on the left side of the stem.
Note that the crossbar is not usually the hairline thickness—it's often a bit thicker than the hairline or the serifs.
The crossbar can be made from a clipped head serif, and simply extended right.