Fishing is a way of making simple money as a civilian.
How To FishEdit
You will need to go to the store located in Rasman opposite of the Hospital to buy a Fishing Rod.
Then head over to the lake in the North West part of the map. Scattered around the two lakes are white circles, symbolising fishing spots. These are the only areas in which you can fish from.
Press '2'. This will bring up your personal inventory in which you can see the Fishing Rod. Hit 'Use' and it will begin catching fish and depositing them into your inventory. Carry on with this method until you can not carry anymore. Press 'T' to access the trunk of your vehicle, and drop all items. Repeat this process untill both your trunk & inventory are full.
When you have completed the above, you will be ready to sell what you have caught.
Go back to the store where you bought the Fishing Rod from and you will see the option to sell your catches. Fish do not make alot of money but when you are low on cash it helps boost you.