Now, down to brass tacks as it were.
- the grape because it will immediately tell you whether it's the type of wine you like or want to drink,
- the winemaker because some are good and some are not,
- the vintage because some years are better than others.
"Table wine," is a blend of different grapes from different vintages; that doesn't mean it's not good. "California wine" can mean a blend of grapes from anywhere in the state, not just where they grow best. If a wine's from Napa or Sonoma, it will say so.
Don't worry about words like "reserve" and "private selection," Basically, they mean nothing; they're just marketing ploys. Pretty much the same for bin or bottle numbers. However, if you find a bin number from a particular vintner that consistently yields a pleasant wine, time after time, by all means, seek it out.
Labels are like sign posts: they can help you.