How to get good sound quality for your podcast

First off, …

Have a checklist My favorite tool = http://processstreet.com  This tool lets you set up process checklists, and include text, audio, video and images so you get things right every time.  This tool is also great for showing your assistant, your VA, or your teenager how to do some of the steps, so you can get back to higher-level tasks.
 
Develop your podcasting system and  follow it every time.  It simplifies thing immensely and will ensure your show is consistently high quality.You can set up a routine for yourself so that every time you record, you go through all the steps necessary to ensure your recording comes out as clean and clear as possible.

Start with:

Quiet environment 
  Background sounds
  Tell family and colleagues what you're doing
  Put up a sign on your door
  Acoustics
     Room size and shape
    Reflections
    Damping Rugs, towels, blankets, coat closet, etc. specialized tools canvas paintings, squares etc.

     Embrace room characteristics

  Eliminate interference
     Computer hum
     Fan noise 
     Vibration – shock mount or boom stand off the table
     Mobile phones – airplane mode

Microphone
  Selection – dynamic vs condenser 
       Pattern. Omni vs cardioid vs hyper vs shotgun
   Placement
   Stand
   Pop filter

Mixer or interface
   Quality preamps
   EQ
   Gain structure

Headphones
  Closed vs open
  Earbuds vs over the ear

Connectivity
   Skype vs G+ vs others
    Connecting  phones
    Bandwidth
    Use Ethernet

Time of day
   Energy levels and fatigue
   Quiet times vs noisy times
    Lighting

What you eat and drink 
     Avoid extremes of cold/hot/spicy
     Avoid dairy
     Stay hydrated and lubricated
      No ice in your glass

Warm up.  
Physical and vocal exercises
Tongue twisters

Finally, smile. It comes through.

After recording – encode without compression for editing

Run through sweetening tools
  Levelator
  Auphonic

  Encode At lowest bit rate  suitable to your content.  
Mono/stereo

Use quality encoding tools. 
Lame
Fraunhofer
Auphonic
Etc.

Final thoughts
 Perfection is the enemy of productivity
Very good is good enough (unless you're doing a show for audiophiles)
Get started and improve incrementally.  Don't wait until everything is just right.

After all, it's about your content.  As long as it sounds pretty good, folks will enjoy.