I've dealt with this before, as a Special Educator.
I focused on making the connection between the appearance and name. I would restrict the first lesson to pennies and quarters. My goal being to minimize confusion. I focused on making sure that the student knew more than 1 distinction between the two coins so that they can recognize them. E.g. Copper is a different color than silver (usually the 1st difference), Quarters are bigger, Quarters have Washington Pennies have Lincoln (not all Special Ed students will recognize this).
The second lesson I introduced Dimes. They look almost identical to pennies, so we focus on how they are a different metal, so are a different coin from pennies.
The third lesson I introduce nickels, and focus on how to tell them apart from Quarters. (Rough versus smooth edge, Washington versus Jefferson, Eagle versus Monticello).
Once the student can distinguish between the different coins, I then start to draw the connection between the coins and their values. Again go only one at a time with the Special Education kid, because their mnemonic tendency will lead to frustration that the Nickel is bigger than a Dime, but has less value.