One of the advanced techniques brewers use to move their game to the next level is pitching greater amounts of healthy, active yeast. Thus insuring fermentation succeeds without unwanted esters from stressed yeast. Most beers will be better with an increase in the number of healthy, young yeast cells.

Not all brewing benefits from a big pitch. Classic Bavarian Wheat beers have greater banana

My preferred strategy is to create a small volume mini beer in advance of brew day. 

At least 24 hours prior to brew day, activate yeast a good 3 hours in advance of building a starter:

1. Dissolve 1 cup of light DME in 1 quart of boiling water.  Pass through the hot break (5 minutes) before cooling the sauce pot in an ice bath.  This cooling will take at least 15 minutes as the pot should stay covered to avoid infection.
2. Sanitize a half-gallon growler or Erlenmeyer flask, funnel, bung and airlock.
3. Pour the cooled wort into the growler, then shake 30 seconds to aerate.
4. Pitch your activated yeast directly into the growler. Seal with bung and airlock.  On occasion, I have covered with a sterile piece of aluminum foil instead of the airlock, but it is piece of mind to see bubbles escape.
5. If you own a stir-plate, include a sanitized stir-magnet and begin an 8 hour spin cycle fast enough to generate a whirlpool.  Even without a stir-plate, your results will be beneficial.
6. 24-48 hours later, pitch your starter, being sure to swirl in the settled yeast cells.  Expect a big Krausening due to the high pitch rate.

I use light DME to avoid propagating in non-maltose environments. I target the same temperate as my ale recipe calls for, but with lager yeast I like to insure early propagation, so mid to low 60 degrees F works best.

This recipe of a starter produces a 1.040 gravity wort, ideal for low alcohol propagation and very low stress prior to pitching. If the starter is not used in the first 48 hours, refrigerate the growler. Then a day or two before brewing, bring to room temperature, pour off the excess liquid and re-do another starter with the flocculated (sediment) yeast.

Good sanitation is critical as a small infection early on produces a big infection in the end. Wyeast and White Labs alone have 100 billion active yeast cells and a 6 or 7 month best use time frame before half of these cells expire. Therefore, a starter becomes even more important as the yeast ages before using.

As often in brewing, there are many ways to a good result (except sanitation).  This starter strategy is my key to improving my beers beyond the minimum and into champion, award-winning beers.