A Kiss in the Rain

I think it was kinda sweet to take on a cliche like this. It's pretty nice. To start, though, I'm going to tell you that you should step away from the airbrush shading style. It's a beginner technique and while the airbrush is useful in some places, it's very unnecessary to use everywhere as that is totally unrealistic. Don't be afraid to use a hard brush for shading and shining. On the topic of shades, you should always start your coloring processes by deciding a light source and where it will go. Right here, there's no defined light source and it's quite confusing. When you're ready to start coloring, just draw a little sun or something where you want the light to come from. From there you can constantly have a reference and calculate your shades accordingly. Next, you should work a bit on proportioning body parts. The eyes are too big for their heads while the ear is too small. The lips are also a bit too small, making them almost nonexistent. As for the girl's eye, you should move the eyelashes to the front of the eye as that is where they'd logically be. This may be anime style, but it doesn't have to be anatomically illogical. :3
As for the rain, I know how you did this and it's a nice starter technique and in some pictures it can be appropriate. But in a picture that's SO close up, the rain is far too small and white compared to the drops on their faces. I, personally, would draw the rain myself in blue. Or at least take the rain layer, CTRL + U in photoshop, hit Colorize, and change the hue to blue.

I hope I didn't sound too harsh. I just want to give you advice that will help you.