Those two hiraganas are a bit more troublesome to differentiate - they are very similar.

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Notice how they both have two twin strokes on the main vertical line (A.). One difference is that the top horizontal stroke in
ま is longer than the one right below it. In
も the difference between the two horizontal strokes isn’t as pronounced.
Another major difference is that ま has this little circular motion (B.) on the left side which is missing in も. One last major difference is the upward curved stroke on the right side of も。Notice how that curve reminds us of the letter “o” as in “mo” (も).