a few good rules of thumb.
Terminal draw is a big money enabler. True for everything better than moat. A good majority of strong BM enablers are drawers, so, in general,if you see a terminal drawer don't feel afraid about going BM.
cantrips are worse with terminal draw. Especially true of non-village cantrips. With terminal draw you reasonably often will draw your card dead in which case it is no better than a curse.
If you are going BM, don't buy more than 3 terminals. 2 if they are large drawers (draw more than 2 cards)
In order to go for an engine, the engine needs to have a bonus. Torturer chains give a vicious attack. Goons, give a lot of VP, bridge/highway lead to a mega-turns (the former with a good engine present, the latter with good +buy/pseudo +buy) In general, engines thrive with abilities that self-synergize (hunting party/goons/torturer/bridge). As a general rule engines need a good benefit, better than (they can get be provinces). (hunting party being a clear exception)
All of these rules are often breakable and you may already know some/all of them but these are basic things you need to know to pass the beginner threshhold. As for the strong player debate, I would say aim for playing opponents who will give you a 35-40% win/60-65% lose rate, You should still learn a good amount but the play won't be so ahead of your level taht you have no chance. In general, if you can, get players 10 or so levels above where you are. And, more than anything, ask your opponents where you went wrong (if it's not obvious). Most people are happy to oblige