Seeing a ton of social media posts about "Rah Rah Americans! We know how to kick ass in winning revolutions", I wanted to avoid being taken in by propaganda and make sure that something I did a project on back in middle school is actually true. Basically, it was that American soldiers at the time of the Revolution were very sloppy and ill-trained in warfare, especially compared to the British at the time who had all the military tactics. Then I believe it was Baron Von Stueben of the French military (I could be completely wrong on that part) stepped in and trained the soldiers under Washington's command to be able to fight back against the British army. How much am I accurately recalling?
Yes, in many other ways than commitment to the North American theater of war. I'd like to point out that the Spanish joined shortly after the French did. Von Steuben was Prussian, not French, military officer. The Prussians had the reputation of being one of the finest and most disciplined troops in all of Europe. Training varied among continental soldiers. Some officers still used the 1764 Manual of Exercise that the British used, some had regional variants such as Nicola's in Pennsylvania, and eventually Von Steuben's in 1777. I can't say if all Continental soldiers or even American state units used it but the manual became a staple part of the training. I'd like to emphasize that this actually pushed the Continental army to adapt more European tactics of close order and a focus on bayonet work.
Once the French and Spanish joined, after the Battle of Saratoga and surrender of Burgoyne's army, the American Revolution became a world theater. The Anglo-French war of 1778 diverted more resources and soldiers of the British to the Indies, parts of Europe, and India. In order to have enough soldiers, the British war office had to put forth a Recruiting Act in 1778 and any current regiments raised would no longer be sent to the American war, but to the other theaters, or be raised for home defense as the British greatly feared an invasion from France. The French attacked Jersey and Minorca, territories of the British, and then combined with the Spanish they attacked Gibraltar, a siege that went on after the last battle of the American Revolution.
The Spanish joined in 1779 and attacked British held positions in the west. The western theater is one that is overlooked in the entirety of the American War of Independence along with the French and Spanish interventions. The British had a harder time raising soldiers for this theater. Among regular forces in the area, the British had the 16th and the 60th Royal Americans, but would eventually have to gain additional forces locally by means of militia. This theater of war went from the Louisiana and Florida area all the way down to San Juan, Nicaragua (featuring a young Horatio Nelson).
So along with weapons as Iphiko stated, the French helped by spreading the British thin along their territories. Besides the naval actions, the French did have some infantry participate in battles in America. Pensacola being one but also some in the North.