As a beginner, your second piece came out nice!
If you are having trouble going straight or staying on the line, you probably need more tension on your blade.
You want to hear a high "ping" when you pluck the blade.
This project is best using flat blades. I suggest you learn to use flat blades first. Once you have mastered flat blades, then go on to learn spirals. By the time you have mastered spirals, you will know where spirals are appropriate.