More specifically, the problem with your picture (which at first glance is very pleasant, with all the right bits in it for a river & trees shot) is one of framing (or composition, if you prefer). If you convert it to B/W you can see this more clearly. The picture hinges around a point just about halfway down the frame - above this are trees, below is river. Now halves are always bad news for composition - our eye, instead of blending this into a harmonious whole, sees two pictures, and keeps trying to flit between them. The good old rule of thirds, tiresome though it may be, does actually exist for a sensible reason. Part of the cause for this poor framing decision is probably to do with your tripod - having set up the miserable three-legged beast, we are understandably henceforth very reluctant to move it. Whereas a better strategy might have been to ditch the tripod, and "walk the shot", looking for alternative framing choices as the light changed.
John
PS I hope you will forgive me, but I have somewhat brutally cropped your picture just to illustrate the point, setting the tree/river division in a more conventional (and I feel comfortable) position. See what you think.