How do you create a seamless texture in Photoshop? I found this tutorial here which is pretty helpful but it seems to not look as nice as the original sampled image when you're finished. Any suggestions or better tutorials?
You have to visually fix it, and you can't have very distinctive features in any tile. You can use patch, healing spot, and stamp tool to remove edges usually. Sometimes brushes work too.
Use smart objects when designing a texture or pattern. Select a box, make it into a smart object, duplicate it and align. Now double click it and it will open in a new window, resize and float the window so now you will be able to see 1 tile which is a smart object and x tiles the which are the pattern. Any changes you make inside the smart object (and save) will appear as a pattern in the other file. It's a nice trick that helps in polishing a seamless pattern and saves time.