once i get going i don't really "rebuild." if you are very careful about age and expensive contracts, a down year is simply missing the playoffs, but nothing resembling a rebuild.
so, to start, make sure to focus on prospects and not FA. once you have the beginnings of a solid core, well-timed FA signings will catapult you to success. you shouldn't have to rebuild after that unless terrible luck befalls you, which happens.
be systematic about the various ways of collecting talent - when to check waivers, when to do this or that and how - be consistent every year even in "Up" years. never leave money unspent during a season (profit may be a consideration - i save that for future FAs that might not fit otherwise)... by july 1, you know whether the cap space is important to any decisions... make sure to buy as many international amatuers as possible every year... when you see a *super prospect, be willing to go over the cap and accept penalties the next year when signing int'l FA amatuers.
do not get attached to players. emotions cloud judgement. bad judgement brings bad results, barring luck (see Joe Dumars run as Pistons president - pure luck, no real plan or consistent thought employed).
never sign a pitcher to a long term contract if they will be mid 30's plus by the end... pitchers are best young/cheap and upto 30-32 with default aging. if you need to have a couple years beyond that, make sure to check out possible trades the first sign of a talent dropoff. A batter i'm willing to go a year or 2 longer with same give'n take attitude about extra years.
only spend boku bucks on players that will contribute in the playoffs. don't spend 5-10M on a bench player. understand your budget.. if you know you cannot afford 3 players costing more than 60M in total, simply don't do it. it won't turn out well...
what do you need for the playoffs? personal preference, but just be realistic... if you spend 10-20M on your bench and they get 10AB over an entire WS run, what is their value per dollar? nearly worthless.
only spend big money outside of those playoff roster needs, if the budget allows ( over entire contract length and future needs/plans).
e.g. don't have a 20M #4 SP if you are going to run a 3-man rotation in the playoffs.
when you control your budget and maximize your ability to pounce on opportunities (you can't spend money that isnt in the budget! it's 100% your fault when you can't afford somethign you need). you may have to sacrifice a slightly down year for a brighter future, while also avoiding a full rebuild. BUT, you can't always have your eye to the future, either... pick and choose when to go for it in the present, and when to throttle back a bit on spending for the future.
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not likely:
if you have draft pick trading on... trade away picks and any prospect that doesn fit your plans for as many first round picks as you can. you can get the first 3 to 5 picks every year.
if it's not on, you definitely should never have to rebuild, or you've done something wrong.
