Long tail keywords means you can easily reach front page to google easily. There will be very less competition. Short tail keywords means it have good competitions to reach front page to google not that much easy and even for very tough keywords it will take ages to reach front page
long tail keywords are words or phrases that a user types on his/her search tab if he uses a short tail keywords but the results didn't give him/her what he really needs. for an example Condotel-this is a keyword Condotel in the Philippines- short tail keyword Condotel in the Philippines with Guaranteed Income-Long tail Keyword
There is much difference between long tail and short tail keywords long tail keywords mean phrase of keyword like "custom and static logo design" and short tail keywords have two or three keywords like "logo design services".