Crackdown/Neighboors Help

[The Train Snake]

Hey, can anyone who managed to get A+ on Crackdown or Neighbours send a message my way, or enlighten me on how they did it or tips they have. the only real problem i have is the beginning of crackdown, the ♥♥♥♥♥♥♥ dog! in Neighboors the big dudes force me to use guns which ruins my combo. Ideas, thanks.