I always found it strange that after animating and making beautiful blocking that we had to go back and spline which would overlap everything causing you to go further back than when you started.

Well after watching webinars on animation mentor, I found that many of the professionals like this little app.

http://www.comet-cartoons.com/maya.html

It enables you to make perfect tangents.

After putting the app in Maya, a little drop down named COMET will appear on the top shelf next to muscle.

Clicking it will bring down a list, at the bottom will be the tangents, click it, set it to 0, and set it on your keys.

Hope this helps.