Here's a few easy Hole in 1s.
Forest Course:
Hole 2: Don't move the direction of the shot. 40% shot power should get you a hole in one.
Hole 4: Don't move the direction of the shot. 50% shot power. Make sure you fire when the front panel of the windmill starts coming up from the front, giving the gap.
Hole 6: Don't move the direction of the shot. 2 and 1/3 bars of power.
Hole 7: Don't move the direction of the shot. 53-55% shot power. This requires a little bit of luck with the bounce.
Hole 9: Don't move the direction of the shot. About 49-51% shot power. Need to be a little lucky with the first hop bounce.
Worms Course:
Hole 1: Don't move the direction of the shot. 76% power. This should be three whole 'bars', and a tiny pixel of your yellow shot meter past the 75% line.
Hope this helps!