Not going to give a huge rate, I'm going to give a few general comments.
Firstly, if you are saving to .jpg which I know you are, stop right now. Look in the last two images around the text, see that horrid pixelation, that's because you saved to .jpg and not .png. It doesn't only effect around text, the whole image is going to be lower quality, it is just more obvious in those examples.
Second thing, you are going to need to do more than put on a gradient map, or even just leave the image as is and slap some text on top and call that a gallery. Then again, something like the second image (rose bud) is way over done and just looks like a low quality bit of mess. There is no appeal with those effects or colours and I honestly can't see why you would do that, it doesn't add anything to the image except make it look worse. Sorry if that was harsh, but seriously, if you are editing an image of a flower without any effects or anything, you are going to want to make it look pretty much the same, with subtle differences to enhance the image. Minimalistic recolours, mainly saturation adjusts, enhancing depth with blur/sharpen tools, adding shadows/light source with dodge and burn tools, maybe even getting rid of some imperfections. Honestly, what you have done is brought down the image and compiled it into a messy canvas with distasteful colours.
Speaking of subtle adjustments, that first image is so hard to see what it even is, and the text sticks out like a sore thumb. Remember, minimalistic, subtle.
I can see you are a beginner, but if you are doing basic photomanipulations instead of tags which require effects, try and keep the original image looking in the best quality and as close to the original as possible. A good photomanipulation should NOT be able to appear edited. Obviously if you view the original and edited side by side you can tell, but without seeing the original, it should appear unedited.
You have a lot to work on, look up some tutorials and read well.
