There are videos online showing how to punch around a circle but I think the easiest way is to use a polar grid. A polar grid is simply a 360 degree circle divided into equal increments. I prefer using a polar grid that is divided into every 10 degrees for ease of use. Others are divided into every 15 degrees or more. If you do a search on Google for polar grids, there are many out there that you can download or click on the image below and save it to your computer.
This is the polar grid that I use:
To use a polar grid, simply place any sized circle on the grid and mark off equal sections or degrees.
I have found that the Martha Stewart corner punches work well on circles that are at least 3.25" in diameter. Some punches require larger circles due to the width of the punch itself but I don't want to get all technical trying to explain this. Simply take a circle, mark off every 40 degrees in most cases, and start punching. To line up your punch, you can do it two different ways.
First off, close the flaps on the corner punch and turn the punch over so you are looking down into the bottom side of it. You will always hold the punch upside down while punching around a circle.
There are two different ways to line up the corner punches, each producing a different effect. One way is to line the tip of the triangle of the inside of the punch with the outer edge of the circle, centering the triangle tip right on one of the lines you drew on the circle. Try to hold your punch as straight as possible every time.
This is what the punched area will look like:
Notice how the design on the punch is moved in from the outer edge of the circle; it does not punch right on the circle. This will produce a smaller end result all the way around than if you line the punch up with the design edge of the punch centered on the lines you drew:
In the above photo, notice how the actual design of the punch is lined up with the edge of the circle, centered right on one of your lines. This also leaves very little paper in between punches that may need to be removed later manually with scissors.
If the circle seems too small or big, move to the next size and try punching. I have found that the corner punches will always work when marking off every 30 or 40 degrees, depending on which punch method you use and what size circle.
Either way you decide to punch, if the punched area is punching over what you previously punched, try the other punching method to see if that works. A lot of this is trial and error based on the size of each punch; but once you get a perfect circle punched out, make a note as to what size circle you used for future reference.
You can always tell how many degrees you marked off your circle after the entire circle is punched by simply counting the number of punches on the circle. If you have 9 punched areas, then you marked off every 40 degrees (360 degree circle divided by 9 punches = 40). If you have 12 punched areas then you marked off and punched every 30 degrees (360 degree circle divided by 12 = 30).
Here are some examples of what the different Martha Stewart corner punches will produce:
And here are some cards showing how the punched circles look:
Above card was made punching around a circle. The rain drop corner punch leaves a triangular shape which is very nice. Compare it to the card below which uses the rain drop edge and corner punches that both come in the Punch Around the Page sets to make a square.
Here are some other cards with punch around the circles:
The above card was made using the Loops Heart corner punch
The above card was made using the Ribbon Loop corner punch
If you are considering purchasing some of the Martha Stewart punches, check out the sale going on at Frantic Stamper here: