It's a lot of fun racking up a multi-star wanted level in GTA V, but unless you want to end up arrested or in the hospital, you need to learn how to ditch the cops. The most effective method is to drive into a Mod Shop and change your car's color when the cops aren't right on your tail.
Another fancier tactic to lose the cops in the first place is to hijack a semi truck and press right on the D-pad. This will detach the trailer and block off small streets or alleyways.
Also remember that finishing a mission will always remove your wanted level completely, which is a big change from the previous games.