Tension, adding stitches, removing stitches, skipping one here, front post there- there are a million different combinations to get a million different looks. Making a flat circle(whether starting a hat or making a blanket) basically comes down to increasing the amount of stitches properly in each round. There are a few ways to accomplish this.
When I'm making a circle, I start with what I call the center, and your pattern calls round 1. This is your magic circle(tutorial on that coming in a future T.T!), or chain that's slip stitched to it's own end AND the stitches in it. For my example, I'm starting a circle that will have 6 SC in it. So I make my magic circle and ch 1, then SC 6 times in the round. Round 1, complete. Please notice that I do NOT count the chain stitch that comes from my join as a SC, this keeps the "seam" a little fuller and less noticable.
So now, on the next round, we want to increase it by 6 stitches, so I will simply ch 1, put 2 sc in the same stitch as the chain, and 2 SC in each of the next 5 stitches. 6+6=12. Because I join and put my stitches right next to the chain, that last loop, while it looks like a separate stitch, is actually just the 2nd half of the join stitch and we do NOT put any stitches in it(see photo) because we've already completed the stitches in this loop.
Now comes the part where people get confused. But remember, we're only increasing the round by 6 stitches. On round 3, that translates to 18 stitches (12+6=18) So, for my personal preference, not counting that original ch 1 as a stitch, I SC once in the same stitch as joining, and SC twice in the next stitch. On a coincidental note, that means I'm putting 3 stitches(current round number) into 2 stitches(previous round number). By using this method of putting 1 stitch in my starter, when I'm approaching the end of a round, I know that I will end with a double stitch directly before joining, and if I don't have a double stitch in my last stitch of the round, that I've messed up somewhere and need to recheck my work.
So now we're on round 4. That means 4 stitches into 3. So I ch1, sc in same, sc in next, and 2 sc in next. 4 into 3, that's easy! And because I started with 6 stitches, each round will also have the same amount of repeat(groups of 4 stitches for this particular round), and 4x6=24.
And so it goes. While I took the pictures at an angle, note that it's laying flat on my desk with absolutely no shaping.
KEY POINTS TO REMEMBER:
~ Increase each round by the amount of stitches in the center/first round
~Current round number of stitches into previous round number of stitches and repeat as many times as stitches in the center(This only sounds complicated, it's really not!)
~Do not count the chains that come out of a join as a stitch for a fuller, less noticable seam(unless you're using varigated)
~Start each round(after 2nd round) with a single stitch so a double at the end.
~Each round will have the same amount of double stitches as the amount of stitches in the center.
~A chain coming up from a join is in the center of one stitch, even though it looks like 2.
Happy Hookin' ya'll!