How to write distinctive letters?
This is more of a handwritten or drawing style question. Lets say I draw letters. How do I make letters and numbers distinct? For example the number 0 has a line through it as well as 7. If I looked at letters l, capital I and 1 may look alike.
How do I draw/write numbers and letters distinctly?
Before you try figuring out how to draw letters and numbers distinctly, figure out which letter/number pairs are giving you trouble. Some differences between letters, like the difference between the large and small C, S, and Z, are not easy to do differently, as they are the same letter only different sizes.
Here are some examples of things I've seen people do to distinguish glyph forms:
1, you can opt to draw serifs on the
1 (like they have in the monospace font: compare I and
l as the only straight line.
Z, you can draw the
2 with a loop (like a cursive Q) or put a line through the
S, some people put the upper bar of the 5 a bit lower. (It's mostly people from Asian countries that do this, in my experience. )
q, you can draw a hook or loop on the
q (This one might not apply to you; but I draw my 9's and q's the same way.)
Drawing a bar on the 7 is only necessary if you normally draw 1 the way it appears in this font, instead of with the bottom bar like this:
As DA01 said, if you need the letter forms to be recognizable without any context, then it's not a good idea to use symbols that are indistinguishable from each other or that could potentially be confused (for example, the Magic the Gathering rulebook does not use "l" or "o" for letter sections because they could be confused for 1 and 0).
It would be a snide answer to say "to draw letters distinctly, draw them distinctly," but it points to a truth - letters that look the same do so because someone drew them to be the same. So draw them differently.
The challenge, of course, is doing so in such a way that is still legible. You can do something like Wim Crouwel's New Alphabet, but people will struggle with it. When we talk about legibility, we talk about what is most readable to people, and what is most readable to people is what they're most familiar with.
Therefore, the best way to do draw distinct letters is simply to study lots of letterforms. See what has been done before you and adapt it to your own style. Open up your graphic editor and look at a capital I, a 1, and an l in many different fonts, side by side. All three glyphs may have one thing in common - a vertical stroke - but some fonts find ways to differentiate.
For example, look at the font Consolas if you have it (it's the font that's in the text editor for me as I answer this question). You'll see that the capital I has horizontal bars on the top and bottom, the 1 has an angled stroke up top and a horizontal line on the bottom, and the l has a horizontal stroke on the bottom, half a horizontal stroke up top, and the vertical stroke is a bit taller. Three letters that could be the same but end up looking different.
Here's a helpful link* - a beautiful illustration by Jessica Hische that shows a ton of ways to draw the letter "A". Maybe this will inspire you.
* I couldn't find the original post...would prefer to link to her site directly if it's still available.