The most important part of the first aid kit is not the kit itself. It's the correct knowledge on how to respond.
Take a first aid course from a certified provider.
At least know what all the items in your first aid are for and when you should use them.
If there are things in your kit that your training disagrees with discard them.
There are items, like tourniquets, that your training level does not cover make sure that it is clear that they are not to be used unless by a qualified person or advised by a professional.
I personally am certified in standard and remote area first aid.