To easily defeat Doc Ock, when your Spidey Sense triggers before he extends his tentactles towards you, enter slow motion, jump over the tentacles, and land next to him. His tentacles will be unable to hit you for a few seconds. Use this time to attack him, them jump out of the way. Shoot impact web from a distance until the tentacles extend again, then repeat the process.
Collect special move upgrades in the following chapters in the corresponding locations:
CHAPTER - LOCATION Chapter 3 - Continue to the right until you reach a train station. Then, look under the electric trap. Chapter 7 - At the start of the chapter, move to the left and get to the top of the building that is farthest to the left. Super jump, then web sling to the right at the top of your jump. Avoid the helicopter and collect the upgrade. Chapter 9 - Located high above the movie theater. To reach it, super jump from a high ledge and swing around until you see it. Chapter 11 - Keep going right though the level until you reach the train station, over the electric trap. Keep swinging while holding up Left and Right until you reach the hidden power-up.
When Mysterio divides, keep shooting until you hit the real Mysterio. Then, quickly tap Y. He will be invisible at the same location where he always ends up. He will remain this way for the remainder of the game.