I changed my handwriting font years ago for precisely this purpose, and I have continued to tweak my letterforms over the years, using the algorithm of changing the form of whichever letters seem to generate the most confusion. Here is my current font:
A few notes about these letters:
Capital letters aren't listed, but my experience is that they're all fairly straightforward. Just make sure to use print letters instead of cursive.
It's crucial to have versions of a, b, d, p, and q that can be written using a single stroke. If you draw your circles and stems separately, they will constantly get disconnected, which vastly decreases legibility.
I often omit the bottom "tail" on the f when writing it in the middle of a word, but I always include it when it's part of an equation. Similar statements hold for the top curve on the i. I will also draw a 1 as a simple vertical line if I think it's clear from context.
The l (ell) is my newest letter, and I'm not really sure about it yet. I tried using a cursive $\ell$ for a while, but it never looked good inside of words, and it still wasn't very legible as a variable. At present, I am often omitting the top and bottom curves when the l is part of a word.
The tail curve on the t is crucial to avoid confusion with a + sign.
The initial curves for the v and w are quite helpful for legibility. I also think v's and w's are more legible with relatively sharp angles, as opposed to a curvy cursive approach.
The initial curve on the x is absolutely essential. This will be one of your most used letters, and it really helps to get it right.
I also think this curvy version of a y is easier to read than a two-sticks version. Among other advantages, it can be drawn in a single stroke, which avoids disconnection problems.
The line across the z helps avoid confusion with the number 2, and the line across the 7 helps avoid confusion with a variety of symbols.
I don't seem to be able to draw a curvy-bottom 9 that looks good. I wish I could.
This version of a 2 is much clearer than any version with a loop on the bottom.
I tried drawing a final loop on my o's for a while (like a cursive o), and it didn't work out.