Hello Codeforces!

On today's contest, Codeforces Global Round 26, I lost a ton of rating because of many Wrong Answers and I was very slow today. Does anyone have any tips for avoiding wrong answers? Does anyone have any tips for getting faster at solving the easier problems?

Also, for today's C1, it took me forever to come up with the idea for how to solve it. When I solved it, I was so frustrated because of how simple it was. Do any of you have a way of looking at problems that helps you solve it? I've noticed that easier problems tend to have a greedy/brute force solution to it. Do you notice any tendencies of greedy methods?

Thanks!

UPD: Even if you think that I am stupid and downvote, please answer my questions to the best of your ability. Thanks again!