Aiming your bubbles in the Puzzle Bobble games can be a little tough, you have to occasionally bounce your bubbles off the sides of the playfield to get them into the positions you want, which can be kind of tough without your guide there to help you.
But, if you think back to your high school physics class, specifically the principles of reflection, you won't need that guide.
Basically, the principles of reflection state that the angle that something hits a flat surface is the same angle that it's going to leave that surface.
So if you check out the geometric pattern in the background, you can use that to gauge where your shot's going to go by following an imaginary line that cuts the squares where you're aiming. This works really well if you aim so that you're going from corner-to-corner, making really easy to follow 45° angles.
Or you could just lose and continue and get your guide back for one round. Your call.