Where should I mark seams for UV unwrapping?

This is one of my first models that I have textured, but I think I’m marking the seams in the wrong places or something, because there is a point in the texture where it visibly stops:

What am I doing wrong?

Maybe try: U + CubeProject.
This could solve the problem

That didn’t really work

Hm I think without changing the texture you’ll always have seams.
But maybe projection painting works for this case
Example video:

If you map a simple image onto the surface of an object, that image must line up perfectly wherever the seams are, because it repeats there. That can prove to be very difficult to make look right. The projection-painting technique allows you to basically “spray paint” your texture onto the object, and with that technique you can hide the differences at the seams. (You are creating a custom image that will be the one actually mapped to the object, using pixels taken arbitrarily from one or more sources at your artistic discretion.) But, you still probably want to keep the seams out-of-sight unless you know that the viewer will never get a too-close look at them. For instance, in a baseball bat, the seam is on the back side and we never show the top or bottom.

Hi. have a look at this product and see how it was unwrapped.

You could try box mapping. In the image node there is a drop down which is by default flat, change this to box, and connect a texture coordinate, generated to the vector input of the image node. You can adjust the blend of the seam. EDIT: In this case you don’t define the seams or UVmap, its generated.

You can skim this for an idea.