Oxidation is one of the most common faults among homemade wines. The Wiz has some tips for minimizing exposure during racking along with advice for how to read fermentation temperature, reducing reductive stink with copper, and carbonating a dessert wine.
Bottling is typically the final step towards producing wine where a winemaker can foul things up. Get some recommendations from the Wizard on when and how to bottle your wines. Also get some pointers on proper etiquette of being a wine judge.