Calc Help

I took Calc 1 and failed. I struggled to pick up the basics. I struggled when I needed to diferntiate for y instead of x. I got more lost when it was change of rate. Like a water basis being filled up and you needed to figure the rate of change. By the time we got to integration I was done. My goose had been cooked. Going to retake Calc 1 again. Any suggestions on how to succeed better the second time?