How to write \mathcal letters by hand? [closed]

Solution 1:

You can try to imitate my calligraphy, follow the one in the other answers or develop your own.

http://www.myscriptfont.com/

http://www.fontlab.com/font-editor/fontographer/

Solution 2:

Per OP's request I'm posting my comment as an answer.

I would write $D$ in the same way which you use in handwriting when text consists only of capital letters (resembling $\mathrm{D}$), such as in the following picture, which I downloaded from here

And for $\mathcal D$ I would use the usual way for handwritten capital $D$, such as in the following picture, which I found here.

Solution 3:

To give a slightly flippant answer: put an extra loop somewhere. It doesn't really matter where you put the loop, a loop is necessary and sufficient for your audience to think it's calligraphic.

Solution 4:

How curious; when I was younger lots of people were struggling to find a way to get the things they knew how to write on paper or on the blackboard into print in a recognisable way, now it is the other way around. Anyway, in writing there is no absolute uniformity and different people write the same thing in many different ways (when I started teaching in France, I had to get used to the fact that students here write $z$ in a way that to me looks perfectly like a $y$, but they write $y$ just a tad differently). Just make sure you write your $\mathcal D$ in a way that looks "handwritten" and somewhat resembles a "D", but sufficiently different from how you write $D$ (and much depends on what that is). Personally I tend to make a little loop at the bottom left of $\mathcal D$ to suggest it is written in one continued stroke (which is indeed they way I write it), while $D$ has two separate strokes.