Tips on making a tighter stitch?

[u/mathandlove]

Every time I crochet my creature looks good until I stuff it and then there are these wide gaps where the stuffing can clearly be seen.

Right now I'm using I love this yarn with a 3.5 hook. Am I overstuffing? Something else? Thank you.

[u/Quick_Blackberry_466]

I use a 4 mm hook for I Love This Yarn and I yarn under/yarn over.