How can stitches become more even?

Dear users, dear authors,
are there any tips for achieving an even stitch appearance when knitting and crocheting?

You get an even stitch pattern through practice, practice, practice... ;-) !

But there’s a simple trick you can use to improve the stitch pattern afterward:
By soaking your work! Place the finished crocheted or knitted piece in lukewarm water and move it very gently at first. Let it sit in the water for a few more minutes; this relaxes the stitches and the yarn, and everything becomes smoother and more even.
After that, gently squeeze out the water, roll the finished piece in a towel and gently squeeze it again, then shape it as needed and let it dry flat. You’ll see, this helps in most cases!

Best wishes, Annette

For me, the stitch pattern is more even when I use thin knitting needles.

Even when I knit in the round—that is, when I only knit without turning the work—my stitch pattern becomes more even. 

In general, practice definitely helps. If you knit or crochet a lot, you’ll eventually keep the yarn tension even without even thinking about it.

I prefer crocheting, and from my experience, I can say it’s better not to pull the stitches too loosely. The larger “loops” make the stitch appearance look more uneven.
I keep the yarn tension quite tight (I always wrap the working yarn twice around my index finger) and I only make the loops I pull through with the crochet hook as large as the size of the hook itself (once I’ve pulled the loop through, I don’t make it any bigger). 
This makes the stitch appearance tighter, but also much prettier and more even.

And if any looser stitches do sneak in, pulling or tightening them a bit in all directions helps.

Warm crochet greetings,
Ines

For crocheting amigurumi, I recommend the “yarn under” technique. With this method, you bring the yarn over the hook from below. This creates an “X” pattern and makes the stitches look neater. It also gives the figure more stability, and especially with darker colors (black, dark blue...), the stitches are tighter, so the stuffing won’t show through later when you’re stuffing it.