1.Improve your flexibility (so you can bend over more).
2.Use the drops more (it takes a bit of time, but you get used to it).
3.Lower your stem/handlebars (a bit at the time) by losing spacers.
4.If you get to "no spacers", can ride on the drops and still want more, its time for a new bike with shorter hadtube/ more aero. Or go for a TT bike (better than aerobars IMO).