Hints and tips on taking over another family's compound:

1) Fully upgrade your health, shooting, and Street Smarts (or close to fully upgrade). You can also upgrade the others, as well, but those first three are the most crucial.

2) Make sure you have at least two level 3 weapons. I'd recommend the Level 3 Tommy Gun (Dillinger) and the Level 3 Magnum. Also, make sure you have at least 2 bombs (you'll need them to blow up the two houses in the compound) and a full stockpile of dynamite and molotovs.

3) Try and take out all (or at least 90%) of a family's businesses and before you tackle the compound. If you eliminate their businesses first, there will be fewer soldiers to deal with on the compound.