First off You will need the same about of intake that you have you need the same outtake fans to improve airflow so say your intaking 30 feet cubed a minute then you want a outtake fans of 30 feet cubed a minute. = Good airflow.
my first one so go easy on me.
Step 1: INTAKE
Step 2: Big Boy Fans
Now those numbers see i have a 2.2 meters cubed intake a minute now i have a output of: 3.4 So thats good its taking more air out than in so we got a vacum !! Well Next is Airflow look at my next diagram.