The first step when creating amigurumi is usually the magic adjustable ring. If you are unfamiliar with this technique check out my post here on how to make the magic ring. The magic adjustable ring creates the foundation while also closing up the hole that would normally occur when creating a foundation chain and slip stitching it into a circle.
When you are working with rounds I have found it very helpful to to count a specific way to keep track of the row and the number of stitches. If your foundation starts with 6 stitches, then you will be working in multiples of 6. If you are starting with 5 it will be multiples of 5. How so you may ask? Each time you have to increase stitches or decrease stitches, so if you do it correctly it will be multiples of the number you started with. The easiest way to count them is to remember what multiple of your starting number comes next. So for 6 the next row will have 12, the next will increase to 18, then 24, etc.
If you start with 6 stitches in your foundation then to increase that you will make 2 sc in each sc in the foundation. This gives you 12 sc. So naturally you will want to increase again and what multiple of 6 comes next? It's 18 of course! You are on the third round, so 6 times 3 is 18. You count 1 sc in the first sc, then 2 sc in the next, then 1sc in the next sc, and so on. You could try to remember how many times you repeat the *1 sc in next sc, 2 sc in next sc*. However, I found that the best way to count is to remember that you are going up to 18, and you only sc in every other sc in the round. So you would count to yourself 1, 2-3, 4, 5-6, 7, 8-9, 10, 11-12, 13, 14-15, 16, 17-18. This way you are counting in multiples of 3 since you are on the third row, so if you have to pause you can easily figure out how much more you have to go.
For the fourth row you have to remember that you sc in the next two and 2 sc in the third. This is the fourth row, so when you are counting the 2 sc in 1 sc will actually end in multiples of 4, but ultimately you end up with the next multiple of 6. That would be 24, so that is how many stitches you will have, and this is the number you count up to. It would be counted like 1, 2, 3-4, 5, 6, 7-8, 9, 10, 11-12... and so on until you hit 24.
Start with 6 sc in the magic ring
Row 2: 2 sc in each sc around (makes 12 sc)
Row 3: *1 sc in sc, 2 sc in next sc* repeat 6 times (makes 18)
Row 4: *1 sc in next 2 sc, 2 sc in next sc* repeat 6 times times (makes 24)
Row 5 - 7: 1 sc in each sc in the round (24 sc)
Row 8: *1 sc in next 2 sc, sc next 2 sts tog* repeat 6 times (makes 18)
Row 9: *1 sc in next sc, sc next 2 sts tog* repeat 6 times (makes 12)
**You will want to fill your ball with stuffing at this point**
Row 10: *sc next 2 sts tog* repeat 6 times (closes the hole up)
You can continue to decrease until the hole is completely gone, and tuck the tail in side.
As you can see, each time we increase we add 1 sc before we make 2 sc in one sc, but we still repeat 6 times. They are all multiples of six, so if you want a bigger ball it would go from 24 to 30 to 36 etc.
I hope this helps someone! This is how I keep track of what row and how many stitches I have to make whenever I crochet amigurumi. Comment if you have any questions and I might be able to help!