Those who seek Hashem (Tehillim 105:3)
It may appear that this kapitel
is simply describing the story of the Exodus of Egypt. However, you also may notice upon a more careful reading of it that it describes the progression of events you will experience advancing from level in your avodas Hashem.
Each advance you make will eventually be met with an overwhelming period of opposition. 
Furthermore, you may notice that like Tehillim
78, this kapitel
does not record the plagues in the sequence they are recorded in the Chumash. The order of plagues in this kapitel
begins with the ninth plague – the plague of darkness. Perhaps this is hinting to the fact that when you first make an effort to come closer to Hashem the first obstacles and opposition you must overcome will be the feeling that the lights have been turned out. Neverthless, you must keep walking - even without the sense of vision - until you eventually see a tiny glimmer of light ahead.
 The verses in Tehillim
105 can be divided as follows:
1) Beginning: 105:1-15
2) First opposition: 105:16-19
3) Overcoming first opposition: 105:20-24
4) Second opposition: 105:25
5) Overcoming second opposition (exponentially more intense and lasting longer than the first wave of opposition): 105:26-36
6) Hashem’s assurance if you remain steadfast: 105:37-45