The British had a advantage with their army being more experienced compared to the militias of the colonies. America won with their superior tactics.
Weakness in the Confederation
Every state wrote a constitution after they won the war. Each one was different but written for different reasons: to spell out the rights as a citizen and to limit the power of the government.
Admitting New States
We want to become a state
The agreed upon document had little power over the states in fear that the government would gain too much power. The power it did have though had to be negotiated from the states.
Since America owed money to other countries and couldn't tax citizens , they asked the states, who rarely helped. This made the central government money worthless so each state printed their own money causing confusion among the citizens.
To become a state a land area has to have 60,000 free settlers.
After the revolution time the country fell upon a depression. Farmers were in high demand to make as much food as possible so farmers took out loan to do that. When the demand fell farmers were left with lots of debt and little means to pay it. This led to Shays Rebellion.