Cupcake recipe makes 24 Cupcakes how can I make it into 12 cupcakes?

Half the amounts of ingredients, like using 1/2 a cup instead of 1 cup.

You have two options:

1/ Make the cupcakes twice the intended size.
2/ Halve the quantities in the recipe.

No offence intended (I'm just trying to save you a lot of trouble) but if you REALLY needed to ask this it's not a good idea to try baking.

Divide it in half. Jesus.

Make the whole recipe and throw half of it away.

Obviously by cutting the recipe in half. Half of everything except baking time.

/facepalm    .

Use a muffin tin rather than a cupcake tin. Muffin tins generally have 12 insets, cupcake tins generally have 24.

maybe you shouldn't be using an oven--just get them at the store next time you go...

half the recipe.
Basic math, there sparky.

Reduce the recipe by half

Provided you want 12 standard sized cupcakes, just divide everything in half on the recipe.  Some items might not transfer over so you may have to approximate on some things like if the full recipe called for 3 eggs, then you would need 1 and a half which would be a little tricky to do accurately.  

Make the cupcakes twice as big as normal, or just cut the recipe in half.

If you can't half the amount of ingredients easily, you could freeze half the dough.

Use half of all the ingredients.

Use half the ingredients or make the cupcakes twice as big by using muffin tins.

you can use a larger tin, or just divide the measurements in half

Just use 50% of the amounts of each ingredient and you will have enough for 12 cakes.

Half the ingredients. But it might not be possible if you have to half an egg. 

Make the 24, sell 12. Keep the profit to pay for the 12 delicious cupcakes you can now enjoy at no monetary costs. Or you could half all the ingredients and try it that way.

Half the ingredients for everything. If the recipe says use 50g of something then use 25g. I do it all the time when I am cooking and baking. If the recipe calls for 1 egg then mix the egg as normal but do not add it all to the recipe.