Get some formal training, constantly keep on the lookout for new tools, and tear apart lots of other people's products to see what the competition is doing. Signal Integrity didn't always matter. Analog modeling of signal propagation was not necessary. Unfortunately, those days are long gone. Even worse, these elements can cause glitches, resets, logic errors, and other problems.
Terminators help control ringing and overshoot on transmission lines.
As speeds increase, more and more PCB traces will begin to take on aspects of transmission line behavior, and thus will require terminators. Unfortunately, terminators occupy precious space on every printed circuit board, and dissipate quite a bit of power. You will want to optimize the use of terminators, placing them precisely where needed, and only where needed. The exact delay of individual PCB traces will become more and more important . Already, CAD manufacturers are beginning to incorporate features useful for matching trace lengths, and guaranteeing low clock skew.