I know this is an old post but here are some tips you may find useful.
Ripen the avocado by leaving it on the counter top. Depending on how young it is - it'll take a day or two.
To check for ripeness, we shake the avocado. If you can feel the pit move inside, then it's ripe. This will be firmer. Waiting for it to be soft tends to make it mushy.
To take out the pit, hold the avocado lengthwise the palm of your hand, then tap the pit with your knife. Give it a turn then pull.
Slice the fruit in the peel, then scoop it using a large ladle. No messy hands.
Hmmm. What is it with me and avocado? This is my 4th post, and the third was about avocado too. Just my luck.