Id go with a stickier base if you are using a base already. Also, try using the e/s wet, or with mixing medium or saline.
Id say part of it is practice, takes lots of that, part is brushes, I really noticed a difference going from crap brushes to mac brushes, but thats me personally, the last part being a good base.
When or if all else fails, use your finger to blend or smooth out the e/s!