Playa Del Rey
There are a lot of possible strategies in this game, but none
with a lock on correctness.
Selecting pieces? Big ones are good for blocking, small ones to fit in tight spaces.
Selecting goals? Early you get to choose the big numbers; and if your memory is good, you can revisit the same pile later and see which goals have been selected by others. Or maybe small numbers are better, because they're easier to achieve - you can set up two three's on the board (for insurance) but only one six. Or maybe it's better to wait until late to select goals, so you can select goals that appear to already be locked in.
Placement and sliding? There are limitless possibilities in the opening and mid game - but as the board begins to fill in, it becomes more and more difficult to make changes. Playing several slides in a row will definitely tip your hand. If you have extra coins, a little strategic randomization will upset your opponents and mislead them about your intentions.
The only problem we had was very near the endgame, AP set in. I think this could be fixed by introducing a "pay to slide" rule with a sand timer. IE; you get 1 minute for your move, and pay 1 coin per minute for extra time. If your time has expired, you can only make the mandatory placement action.