Need help to improve website speed and megamenu

Hi There,
As per GTmetrix my website sprihi. com speed Grade is D. Need inputs to improve the speed Grade to A. Also need inputs how to stop the flickering effect when mouse moves fast on the megamenu ( drop down menu )

The GTMetrix report highlights the below links which is taking maximum time to load, can anyone help what are these links for and can they be avoided/ improved