The Yetzer Hara as Passerby, Guest and Master
Rav Tzadok maps the three stages of the yetzer hara, and for each stage names the tool that works against it.
The Gemara says the yetzer hara is first called a walker, then a guest, and finally a man. Rav Tzadok reads this as a map. While he is only a passerby, the task is not to let him enter the house of your heart at all, and anger at him from the yetzer tov can be enough. Once he has come in as a guest, a person must sink his heart into the words of Torah, and Torah will drive him out. If he has settled and claims a place as though he had earned it, a person turns to Krias Shema and to emunah, remembering that the house has a Master who can remove every intruder. When the heart is filled with the awareness of Hashem before him, everything opposed to Him dissolves. No one begins at the top rung, and each stage prepares the next.
Source: Machshavos Charutz 3:2
Think of one temptation that tends to settle in, such as a habit of wasting time or a sharp word you often let slip. This week, try to catch it at the very first moment, while it is only passing by, and say no to it right there. If it has already come in, open a sefer and learn for five minutes. If it feels at home, say Shema slowly and remember Who is in charge. Take it one step at a time and be patient with yourself.