The release schedule for Magic is given here.
Rivals of Ixalan comes out January 19th 2018. We'll call that T.
T - 40 Leaked cards start to come out. In fact one card has already been leaked. This stage isn't really part of a systematic approach.
Approx T-21. Set is officially spoilered. We find out every card in the set. At this stage it's worth listing the Flash and Instant cards in a spreadsheet by colour and trying to learn them. You're a much more effective player if you know the implications of your opponent having one black mana open.
T-20 to T-14 Youtubers like Nizzahon and The Mana Leak evaluate the cards. I make a spreadsheet just listing the As and Bs as they evaluate the cards. My process when building a sealed deck is to pull all the As out then craft a strategy around playing them. These are likely to be the bombs. I won't always get them all to work, some cards don't splash well but I think this is a good place to start. Note these sites and the later Limited Resources are evaluating for draft, a faster format. So for Sealed I need to overrule their verdicts from time to time.
T-14 to T-6 Limited Resources release their set evaluation. I check if there are any more As and Bs that I don't have yet in my list from the other guys.
approx T-14 Loading Ready Run do their pre-pre-release show which is a good opportunity to see people play with the cards.
T-6 : the set launches. I think about whether I want to go to a shop and play MtG physically. Usually I don't go but I did enjoy the Hour of Devastation prerelease I went to at Dark Sphere in June.
T-4 MTGO prerelease. This is the opening of the gold mine. Right at the start the value of the cards one opens probably covers the cost of entrance so basically you're playing for free with all prizes as pure profit. Also many opponents are new to the format or rusty at Magic and make mistakes.
T-4 to approx T+30. Playing these games is amazingly effective and powerful tapering off over time. Each day the value of the cards opened decreases, the expertise of average opponents increases and the chances of getting a newbie opponent go down.
I think I didn't do enough Sealed this expansion and plan to really hammer the game in late January.