Welp here is some things you can do to prepare.
1# Stack up on books.
As we know, the crafting recipe for a book will become more expensive so get a TON of sugarcane and craft away.
2# Get cocoa beans.
We will be able to plant cocoa beans onto jungle trees in 1.3. This would make for a nice farm combined with wheat.
3# Enchant!!!!! (SP only)
If you have more than 30 exp enchant away. (You probably already updated your sp world though.)
4# There is no number 4
5# Hold off making things with slabs.
Placings slabs will be made a lot easier in 1.3 (Thank God.)
Thats all I have so far.