Some tips from the self proclaimed gif master, aka me.
1. If you want to make a good quality gif for a website with a file size limit (tumblr, etc), where it says SELECTED RANGE in the first step, make it 2 or even 3, and then do the math to change the delay time. Natural motion for no skips is .04, so if you take out every other frame, it becomes .08 (I use .075), and for each third it becomes .12 (.11)
2. If you're doing ATRL AVI sized gifs. Crop to a square (in photoshop, hold down SHIFT, it automatically makes the crop selection a square), Go to IMAGE/IMAGE SIZE, resize to 127x127, go back to IMAGE/CANVAS SIZE/ change it to pixels 125x125 (photoshop likes to add a pixel of white lines around resized gifs, this eliminates that)
*Also apply this to any gif you're ever making, always allow for 2 extra pixels (1 on the left, right, top, bottom) so tumblr gifs (500Wx280H) should be resized to 502Wx282H then canvas sized down to 500Wx280H.
3. Select all the frames in the animation toolbar with shift, go to the top right, click the lines with the upside down triangle. CONVERT TO TIMELINE. Go to your layers toolbar, select EVERY layer. Go to FILTER/CONVERT FOR SMART FILTERS, then go to SHARPEN/SHARPEN, usually sharpens perfectly, but you can change the opacity at the bottom of the layer on the layer toolbar (unlimited layers)
*Save the gif, reload it and change the framerate back to .04/.075/.11 etc etc, and make the loop FOREVER.
4. I hardly ever edit the colors of my gifs, but you can if you need to buy just building onto the last step, making them SMART FILTERS and change the BRIGHTNESS/CONTRAST/COLORS etc etc.
That's all I have and here's some of my gifs for examples.
I convert to video timeline & set it to like 25-30 fps but nothing really helps. 
