I'm nowhere near a master and make a lot of stupid mistakes. But my relatives think I'm worrying to much about those, nobody notices, nobody cares besides me. But next time I do the same thing again, I know. If it really counts or is entirely botched I just redo the piece.
Wood is similar to clay. You just try by sawing pieces in two smaller pieces, start to grind them, then come different sawing tools and techniques, then finishing (oil, laquer, etc.), then routing... Obviously you start with smaller, simpler things.
And in contrast to what others said: Don't be afraid of mistakes. A dent is just a dent, the piece is supposed to "live" anyway. Your kids will put their teeth in soon. And a piece of wood can be replaced cheaply (don't start with ridiculously expensive hard woods obviously). You can always cut a new one.