1. Get to planning! Granted, I planned 5 years ago, but not as far in advance and more elaborate as I do now.
2. FP+. Whole new way of touring. Like PP stated, learn how to work it. Some love it, others hate it. Just go with an open mind and come to your own conclusions.
3. There really isn't a "slow" time anymore.

Sure it isn't always Christmas break busy, but the old days of crowd levels 1 and 2 are gone. Yes, let's cry again ...

4. ADR's. You have to book using a CC now. People went cuckoo booking reservations at every place and never showing up so they had to curb the abuse. It's not a big deal, just something new. You can cancel your reservation anytime up to 24 hours before and will not be charged for a no-show. If you do no-show it's $10 a head.
5. Have fun! It can get overwhelming all the stuff you read. Planning is supposed to be part of the fun. If it stops being fun, take a break.