That's harsh Larwick..You should look back at FF3 or 2.
And those are horrible examples to look at, and restriction-bound at that. So no, the palette is not good, neither are the tiles to be honest. The high saturation and contrast are really hard on the eyes, and so is the repetitiveness of the tiles and texture that makes it really busy. Before composing a mockup you should see that you have enough tiles to break it up and smooth it out more. Transition tiles between the different ground types for at the very least vertical and horizontal borders, diagonal ones provide even more possibilities to break the grid and make it more interesting. There are great examples of rpg tiles in the very tutorial you were inspired by. I'd say work at a slightly larger scale and don't texture
anything manically, flat spaces can make for nice stylistic effects, and, most importantly, clarity. One of the most important things about how an image is perceived is the distribution of values. What you have here covers the darkest darks and the brightest brights in
every tile, which makes it basically impossible to clearly make out neither dark nor bright objects, since it's already all over the place. My recomendation would be, that you look at other examples of professional work, and start over.
About the isometric piece, yes, please always crop the canvas to a reasonable size, and again, don't use too saturated colors. It seems to be a really early wip, on which I cannot comment much. I think you should work on it more until you get to a point where you yourself do not know anymore how to improve it and then post it again.
VicorR, you already have been notified about this, and if you keep posting such unelaborate posts at such a fast rate, you'll have your post-count zapped, because most of the time it seems that you are just posting to get it up. You are a top candidate for a strike.