In the King James Version, Romans 12:9 reads, "Abhor what is evil; cleave to that which is good." The amplified version reads the same verse, "hate what is evil [loath all ungodliness, turn in horror from wickedness], but hold fast to that which is good."
If we are going to be fishers of men, we need to do just that. We need to hate/abhor evil (thoughts, desires, actions, suggestions, attitudes, etc.). We must 'loath all ungodliness.' In other words, if it is evil, you should want nothing to do with it. Look at your life, hold on to a good attitude, good thoughts, actions (such as helping others), desires, etc.
Does this mean we are to be perfect? We are human, that isn't possible. We do need to do our best. We need to ask God for help, and when we slip we need to ask for forgiveness. That is why God sent Jesus in the first place, so we could be forgiven. If it wasn't for Jesus coming, we would all be doomed. If God didn't love us, why would be have sent His only begotten Son to go through all that Jesus went through.