Grammar

Grammar! Why is English grammar so confusing? I studied grammar for many years at school and I still don't understand when to use a tense. Is it the simple present or the present perfect? What's the difference? My teacher tells me to keep visiting grammar websites and doing the practice activities. She told me to look for patterns, but I'm not really sure what she means. She also told me one of the best ways to learn grammar is to read for pleasure. She said that way I'll keep seeing good grammar and it will slowly come to me. I think the best way to learn grammar is to write and let my teacher point out my mistakes. Do you have any good tips on how to learn grammar?