Think of patterns as your blueprint, they are a crucial part of any sewing project. Patterns can tell you a lot about what the final product will be, but some patterns can be unrecognizable to their final outcomes.
How to Design them
What is a pattern exactly? Patterns are used in sewing to tell us what shapes should be cut out of our chosen fabrics. They are flat shapes and can tell us a lot about that project, but they can't tell us how to put them together. Some patterns have markers, some don't, it depends on where you get them or if you yourself add them. Some patterns have built in seam allowances, while others don't.
As the old saying goes, practice makes perfect. Designing a pattern is long project, and you’ll likely make several prototypes before you’re happy with the final look. A good way to start practicing making plushies is with pre-made patterns, a great place to look is Etsy for artist made plush patterns. Most come with their own tutorials but some require knowledge on sewing techniques. This will help you understand fabric shaping and will prepare you for designing your own pattern. Another way is to study plushies and find the seamlines, think about how those particular fabric shapes make a 3-D shape once sewn together.
I made about 10 different prototypes when I was designing my horse plushies, and that doesn't include minor adjustments I made during the sewing process. Something I did often was unstitch certain parts after I saw what it looked like stuffed. When designing a pattern, consider how it will change when stuffed, it will usually look different such as being shorter than the height of the pattern. Some parts will just look funky, check your seamlines for straightness, and if it's not that, back to the drawing board!
If you have access to digital programs like photoshop, you should consider digitizing your pattern. Trace your pieces onto paper and scan it in, then trace them over again, make a new layer for each piece. Make sure your real life paper and the canvas sizes in photoshop match, that way they will a print out at the correct size. If you can't do that, get a folder and be diligent about putting away your pieces; especially small ones.
Remember that regardless of what you do, making even one plushie or starting a business with them is a large investment. You may have to invest in a sewing machine and will have to spend a large amount on materials including fabric, thread, stuffing, eyes, pins, scissors, marking pens or chalk, and most importantly your time. Making plushies by hand is a time-consuming process, however, it can also be relaxing and extremely rewarding.