If you are thinking about the main theme of the novel, you have to look at the narrator and how he develops through the novel and the lessons he learns from this community which is the subject of this work.
In many ways the narrator learns about the values of this community - values which the community shares in common and which have a moral basis rather than a legal one. Legalistic values don't seem to have too strong a place in this community - no one thinks any worse of someone if they have a prison sentence, and sometimes it can make them a hero, as with Popo.
The street very definitely has its own standards which it enforces. There are numerous examples of behaviour which is not endorsed by the street as a whole: the cruelty of George towards his children and his forcing his daughter into a marriage, the beating that Mrs. Hereira's lover gives her etc. Compssion, dignity and endurance are the triumphs of Miguel Street - in comparison with the worldly successes that we tend to focus on. The lessons that the narrator learns are self-respect, beauty and imagination - perhaps the latter is the key lesson, as it is with imagination that the inhabitants of Miguel Street are able to accept each other and also the possibilities which each day brings.
*issues of poverty
*love & family relationship