Avoid Dying Near Cars
When you are hiding behind a car during a gun battle, do not get near the engine. If the engine is facing the enemy, their gunfire can cause it to explode and kill you.
Go to Bruski's Scrapyard. Break into the random car located near the car crusher. You do not need to pick the lock because there are no police nearby. Drive the car into the car crusher, then crush it to get approximately $400. Enter the car you came in and drive it out of the scrap yard through the north exit. Continue on this road until you drive under a bridge. Then, turn around and return to the scrap yard. Another random car will have respawned near the car crusher. Repeat the process as many times as desired. This will also unlock "Proper Scrapper" achievement or trophy easily.
Easy Money, Guns And Clothing
One of the easiest ways is to find a good, expensive car and drive it to Derek's Office to export. You will earn approximately $2000 from this. Of course, it is not possible after you kill Derek so make the most out of it while he is alive.
Another way is to take any car to Bruski's and have him press it. Bruski's scrap yard is located on the north most area of Riverside. When you arrive in the scrap yard simply park the car in the press, exit the car and climb the stairs outside the shed to the control panel and activate the press. You will earn approximately $450 from this. You can fit any number of cars in the press as long as they are entirely within the press.
A more violent way is to find a gun shop, kill the shop keeper, rob the cash register and then take all the guns. This will net you around $600 / $700 in cash. There are plenty of gun shops scattered all across the city so there are lots to choose from. Be careful as the shop keepers are generally dangerous and may shoot you on sight. Just be quick and take him out as soon as possible.
Another good place to rob is the clothing store. Enter the store, point the gun at the cashier to scare her, and just rob the register. You will earn about $150 here. Grab a few new clothes while you're at it. Dress up, dress sharp!
Gilbert Gottfried Reference
In Chinatown, there is a shoe shiner that looks and sounds like Gilbert Gottfried.
Jimi Hendrix Reference
When you crush the car that has the bartender's body in it after Joe killed him, you will earn an achievement or trophy named "Hey Joe". In the Jimi Hendrix song "Hey Joe" the lyrics include the line "Hey Joe, where you going with that gun in your hand."
Zero Wing Reference
When you go to prison and to the yard, you will find a crazy man in the center. He says phrases such as "All your base are belong to us", "Someone set us up the bomb", and "You have no chance to survive make you time", from Zero Wing. If you talk to him, he will run away.