Stars: press and hold the mouse on the Rectangle tool. Select the polygon in the popup menu. Next, double-click the (now) Polygon tool to see its options. Experiment with the number of sides and the Star insert to get the star you want -- the "insert" value defines how much the sides of the polygon are pressed inwards. I never tried before, but it doesn't seem to be possible to alter the value after drawing one ...
Waves: select the pen tool and draw waves one segment at a time. If you need more control, you might want to draw the wave in Illustrator and copy that into ID -- you can copy any path from Illy.
Placing an image into a shape: not sure about the wave ... that's just a single line, isn't it?
Into the star, or a circle or rectangle is easy. First, select the object you want to put the image in. Then, choose your image file with the Place dialog. Be sure to check the "Replace selected item" box. Press Okay, and the image is in the object.
Alternatively, place your image somewhere in the document as usual, Cut, select your object, and choose Edit -> Paste into.
Changing it afterwards is easiest with the white arrow Direct Selection tool. Click and drag the image inside the object to adjust its position, or press Delete to remove.
Nice Trick: an image in a text. Type your text into a separate frame. Select the frame and choose Type -> Create Outlines. Now you can paste in an image just as in the other objects. (Be aware that the text is not edible anymore after converting to outlines.)
> I never tried before, but it doesn't seem to be possible to alter the value after drawing one ...
which is, of course, blatant nonsense. You can select the Direct Selection tool (white arrow) and move each separate point to whereever you want. To quickly adjust the inset value (not "insert" :-P), select just the inner or outer points of the star. In the Reference Point proxy (top left in your Control Bar), select the center point. Make sure the chain icon to the right of the percentages box is checked. Then change the percentage, et voila (as the French sometimes say) -- your star gets more pointy or more obtuse.
One task I have always had trouble with is to draw the traditional 5-pointed star in Indesign, where the two horizontal "arms" are EXACTLY straight. The inset doesn't allow for decimal values (at least in CS2), which is what it would have to be for this.