I've learned a few things in brewing my first 5 beers and I wanted to share some observations:
1. Start a brewing Journal or Notebook - If you don't know what mistakes you make, you can't stop making them. When using a kit I have the kit instructions, but I've also typed out my own instructions so I do things correctly and at the right time.
2. Yeast Lags, Make a Starter - The 2nd and third beers I created took 3 to 4 days to start fermenting, I initially pitched 1 liquid vial into an IPA and a Lager and found out that high gravity beers and lagers can overwhelm small amounts of yeast. So find a yeast starter calculator (like Mr Malty) and start the yeast a few days before you pitch. My last beer took 4 hours to start active fermentation.
3. Oxygenate your Wort - Walmart sells a $6 aquarium pump, morebeer.com sells a $15 oxygen stone. The combination helps improve the initial condition of the wort for getting yeast pitched.
4. Create a Brewpot Measurer - Do the boring work and add 1 quart of water to your brewpot and record the volume on the back of your brewing spoon; so your brewspoon becomes a dipstick. I forgot to add a gallon of water to my 2nd beer and didn't catch my error until it went into the fermenter.
5. Buy a propane stove - The first three beers were boiled on my regular gas stove and I had great difficulty keeping 6 gallons boiling. I purchased a turkey fryer on Amazon for $49 plus shipping and cut my boiling time by 2/3's and I had a lively boil! My 3rd beer was 6 gallons and I boiled off like 1 cup over the hour, so I had an IPA that once it fermented, blew out of the bottle, :-)
6. Can some starter - If you've ever done any home canning, you and inexpensively add 10% to your recipe and create a great starter for the next time you brew a similar beer! So you are able to can 2 quarts of starter for a 5 gallon brew.
7. Be or Act like your on a limited budget - After receiving my $300 deluxe brewing starter kit, I've been doing a lot of DIY projects. I converted an extra cooler and purchased a $37 10 gallon cooler from home depot. I invested about $30 in parts and now I have an all grain system. Morebeer.com sells the same thing for $280. While I'm at it I was able to get a garage refrigerator on craigslist for $50.
If you plan to brew lagers, first make sure you have a spare refrigerator in the garage. This leads me to a few more suggestions:
8. Don't brew a lager until you know what your doing - Get about 10 separate brewing experiences before you tackle a lager. I tackled my Pilsner lager as my 2nd brewing experience. Lagers are really different and have a different learning curve. It will take about 2.5 months to finish my lager; ales take about 4 weeks from brew to bottle drink.
9. Harvest your yeast - There is a great article on this web site on how to harvest your yeast. Why spend $$$$ on yeast unnecessarily? My 1st lager took 4 vials to pitch, my next 3 lagers won't have any yeast cost other than some mason jars, a little distilled water, and some electricy for sitting in my refrigerator.
Finally, if your planning on designing your own beers and making beer from your own design, get some brewing software. I bought beer tools (mostly because I use a mac), but download a trial version and use it to make a few beers.
Hope this helps,