Ok, so I have this cute plaid shirt that I bought thinking the sleeves would be long enough. They were not. In fact the sleeves were so short that adding a t-shirt underneath wouldn't work because the t-shirt sleeves were far too long looking, which it is ok to have long t-shirt sleeves, but in this case it made my broad shoulders seem military-man broad. As I am not a man and do not want to look like one, I opted for another option.
I am going to add 2 sleeves under the original sleeve. Because everyone is different sizes, lengths and not to mention how different each of our shirts are, you will need to follow this advice on how to make the sleeve you need.
Here is my shirt that I am going to do this to:
As you can see, the sleeves are barely there, and I have actually already added one of the sleeves (it is black satin). Adding more than one sleeve will allow me to add length without making it look too obvious I did it myself, and it will go with the ruffled look of the sleeve that is already present to give it a more girly shoulder instead of manly broad shoulders.
I will post pictures next week of the finished project! Good luck on your own sleeve making!