We've been looking at small patterns within the verse, the bridge, and the chorus. What we really need to see is a larger picture of our song. The entire song is actually one complete, and quite complicated, pattern that consists of smaller patterns; namely: the verses, the chorus, and the bridge - in which there are even smaller patterns. In popular music (e.g. pop, rock, soul, reggae, hip-hop, Rhythm and Blues, etc.) most songs repeat patterns. So, if a song has four verses, then all of them usually follow the pattern of the first verse. That's not to say that some of the notes in some lines won't be sung or phrased a bit differently in one or more of the verses, but, in general, the melody and chords will basically follow the same patterns in each verse. When the chorus (refrain) is repeated, it will most likely follow the same patterns it did the first time around in the song. If the bridge is repeated, it too will probably follow the patterns of the preceding bridge.
If you wrote another verse for our song - for example, using different lyrics but the same amount of syllables - you could follow the same patterns by singing the same notes and playing the same chords you used in the first verse. You could then make the third line's melody and chords the same as those in the third line of the first verse. Also, if after the second verse you repeated the chorus virtually note for note with the first chorus, you would probably use the same chord progression as the first chorus.
The majority of "hits" - and probably many of your own personal favorites - contain such patterns. Tens of thousands of popular songs (in all genres) incorporate this song structure. Therefore, by finding the smaller patterns and seeing the larger pattern they belong to, you can learn to play by ear quicker and easier. More importantly, by understanding and recognizing these patterns through careful listening and devoted practice, you will soon be able to anticipate chord changes and patterns - even when hearing a song for the first time!
You will need to begin listening to music in a different way. Instead of listening as a passive spectator, you will need to try identifying the patterns of a song. The human ear and brain allow us to ignore some sounds while focusing on others. That means if you concentrate on the sound of the drum beats in a song you can identify the patterns the drummer is playing by listening to the various drum components (The snare, kick drum, hi-hat, toms). I used the example of drums because they are easier to distinguish from other instruments; however, the same technique of listening can be used to identify guitar chords and solo notes. You need to focus on what one guitar is playing. You might find that listening with headphones helps in doing that because they will block out most other extraneous outside noises and distractions.
If you are having problems listening to just the guitar, break the song down into it's larger patterns. Asks yourself these questions: "What part is the verse?" "What part is the chorus?". "Does the song have a bridge?" Once you've identified those parts, when they occur, and the duration of each part, you can begin to break each pattern down into its' smaller patterns. Once you have identified the smaller patterns you can break them down into their basic chord and note components. If you are still lost, make a guess at the first chord, which will at least give you the key signature of the song. Read the lesson regarding Common Chord Progressions for hints on what chord, or chords, might come next. You will become more adept at using these techniques by practising them repeatedly and often. I suggest you also read about Barre Chords