Innovation plays differently nearly every time you take it out of the box. While long term planning is possible, it is often much more important to seize the best tactical option at any given moment.
Splaying and thus amassing icons is important, as is spending time to accumulate some points. Ihe first few times you play, it is probably easier to focus more on the cards that you have rather than trying to understand every possible action each player could take.
Tips: icons (which appear in ages 1-3) are very powerful early, but can quickly be a liability later if not covered, due to cards like Gunpowder and Engineering. icons begin appearing in age 4. You most likely want them. Being completely shut out of the new technologies can be very painful, as the cards that use can yield many points in the mid-game.
Achieving is almost always the correct action, if you can do so. You might not have those points by your next turn, or someone else could take it first!
Age 9 and 10 cards are very powerful, and can end the game immediately. If you're trying to win by achievements, you want to finish up before the game reaches this stage. Anything is possible in the late game, and your lead can quickly evaporate!
If you're behind, getting to 9s and 10s may be your last, best hope for victory. Remember that if you are behind on achievements, ending the game by drawing beyond 10 is an alternative.