1) First, the Constitution has to be proposed to Congress. Next, Congress has to vote to have the amendment submitted to the states for ratification. Then 3/4 of the states have to vote to ratifify the amendment. Alternatively, having 2/3 of the state legislatures call a convention will also get an amendment proposed, but that has never been done.
Since the government was to be about the people, this long process would ensure that the citizens, or at least the majority of them, would want the proposed amendment. Otherwise amendments would be getting enacted without the consent of the citizens.
2)Judicial Review refers to the Judicial Branch's power to not only interpret what the Constitution means word for word, but to also declare whether actions of government officials violate the Constitution. People had very mixed feelings about the Constitution, making it very controversial. While some argued for it by saying things like the judges having the best position to declare what the Constitution means, others argued against it by saying things like if the judges make an error in interpreting they cat be removed from power.