1. Every day at least donate 100k to your bank just in case of emergency or if you need to train your gun.

2. Then after each drug run I keep half to buy more drugs and the other half goes to my crew. Until I make a profit.

3. Finally always have at least 75k for drugs.

4.(T.I.P) The main way I gain money is MUCs I do about 4 a day. 

Also crimes will start to add up, but remember to start low then do the higher crimes.

Dont get me wrong but isnt that kinda common sense....

Also only  75K for durgs? Wont that be a bit too less if you have arnd 25+ units?

yes but if you note his rank, those numbers are accurate to his rank if you play a lot. at a higher rank you can increase the numbers as needed.