Also, sorry about reviving a dead thread but I absolutely must agree with other members in stating that the importance of training far outweighs what cool gear you bought off of Amazon or what videos you watched on Youtube.
One of the most dangerous things you can have is someone who is confident in abilities that are completely false.
I was a platoon medic in the Airborne Infantry (1/503, 173rd ABCT) and have seen my fair share of incompetent medics who actually made it through combat medic school at Ft. Sam Houston, and they actually received formal trauma schooling!
That being said, having an aid kit is better than not having one, but one should make it a priority to attend some sort of formal schooling on the subject. BLS, EMT-B, various wilderness first aid classes others have mentioned, etc. I've personally taught Combat Lifesaver (CLS) classes to several thousand soldiers from 5 nations and can attest that the more realistic the training, the better your skills will become.
Just having a kit won't make you or anyone else any safer if you don't know what you're doing with it!