In general, if a person acts upon what she/he knows, they will be successful. A person knows the haraam and halal of Allah and hence should be careful and attentive to them. One should act upon the waajibaat. A person is also prone to making mistakes in which case he should ask for forgiveness and should not have this expectation of themselves to reach the status of the Prophets today. It's not possible because the advancement of a person is gradual hence one should continue to strive and ask for help from Allah and through intercession, insha'Allah the situation will be get better. No one can claim that they are perfect believers. The advancement of a person is such that however much they strive, there is always room for improvement. What is important is that a person keeps to the path.
Also know that Shaytan whispers to throw a person off track by making them hopeless. Be careful of these whispers and don't become hopeless on this path.