"It's pretty frustrating having something look great in photoshop, but when its imported it looks awful."
Are you saving it as jpeg with low quality? The standard format for sprites is png, which won't do that.
I've used both PNG and PSD, both which are supposed to be the best to use with unity. However neither worked as I expected.
What are your settings for the sprite inside unity?
I figured it out, well at least perhaps a workaround. I had the resolution set to 72 ppi, which was purely to try to keep the image size small. However if I set it at 300, then reduced the "Max Size" in Unity, the quality wouldn't degrade too much and the size went down considerably!
For settings I just had it set to a simple sprite with mip maps off, point filter and automatic compressed
Resolution doesn't affect anything on your sprites if you're setting the image size in pixels on your editing software. It refers to pixel per inch, which is usefull only for printing material, when you're working with a file that has it's measures in inches, or centimeters, etc...
But your problem lies in Unity. You have a compression problem and you just told me your settings are "automatic compressed".
Change this to "truecolor".