Step 1: Make a lot of money
Step 2: Grow a large penis
Step 3: Show her the results of Steps 1 and 2.
If you want shallow you can have it.
Although I know that it was just for the lulz, I will address the previous comment as serious because it is one of the main misconceptions that males have, deep within.
Step 1 influential but
not essential. Actually, to be accurate, enough money to be self-sufficient, autonomous and being independent, which translates to security which in turn are signs of maturity. That's what girls really dig, the amount of money beyond that is not really important, unless you are targetting gold diggers. ie. if you made a million dollars but still living with your parents, I can bet all my bitcoins that you'll have a tough time attracting quality dates.
Step 2 is not essential
AT ALL. Ironically guys are more obsessed with big dicks than girls. Go figure.
AND also it is impossible to make your dick bigger naturally (ointment, massages, pills, etc...), stop listening to infomercial craps and don't believe what you see in porn, they are preying on one's insecurity... the only somewhat reliable way of making it bigger is with surgeries doesn't actually guarantee a permanent long penis, and even worse, they can leave you limp for life and incapable of achieving orgasms. Big, dead and insensitive, are the potential outcome that you would get. If it works, just leave it. Having a small dick and a huge self-confidence, makes you still an attractive person.
In fact, every defect that you may have, even the physical ones, may be a big advantage if you know how to reframe it properly. It is
how you look at things
what defines things.
Cheers