The Bloods have the average amount of cities for the criminal element, but they're not as consolodated as other gangs.
The Bloods first move should be to build an additional defensive unit or two in each of their cities. Once that task is completed the Bloods should concentrate on taking over the Civilian and Mobster areas near them, and also the Panthers if they should decide to try to take some Blood terrritory.
The First blood milestone should be to clear everybody out of their side of the city from the forest on the East to the Forest in the Middle of their territory. Now expand southward, but not to the island that the Police HQ is on, the HQ is heavily defended and will not fall easily, and you can't get to the commerce island without getting through it first, so we're going to go around it. Conquer the entire Southwestern portion of the map. Once you have completed that, then you can try to take the main island of the city. But when you take the Police HQ, plan on meeting some fierce resistence from the police. Once the Island has been secured, it is up to you to decide who will be the next target.