Before a person does Teshuva he does not have any existence and it as if he does not exist in the world, since it would have been preferable that he had not been born rather then him being born. When he comes to purify himself and do Teshuva then he start to exist.
(Kitzur Likutay Moharan Hayashon Torah 6 Clause 3)
Teshuva Requires Extreme Patience
Teshuva requires patience. As the Sages wrote that a person who comes to do Teshuva is given help from above but first he is told to wait. Therefore when a person wants to do Teshuva, even though he has to hurry and flee for his very life to escape from the darkness, despite this he has to be extremely patient and proceed with great measure according to how he is instructed by the true Tzadik, since it is not possible to enter the realm of Holiness all at once.
(Kitzur Likutay Moharan Hayashon Torah 6 Clause 4)
Teshuva is Continuous
A person needs to constantly hold on to the attribute of Teshuva, since even at the time when a person is confessing and saying "I have sinned", even this he is not able to say with complete purity and without personal agendas. It comes out that he now has to do Teshuva for the first time he did Teshuva.(Kitzur Likutay Moharan Hayashon Torah 6 Clause 5)