@Bruno_Pereira: I’d advise that the most important thing for you to decide in Jurassic World: The Game is kind of the most important thing for you to decide in life:
What’s your main goal?
Sorry, that was deep. Back to the game. It really depends on what you want to do. Do you want to collect one of every creature? Do you want to excel in the combat arena? Do you want to fill all your paddocks? Do you want to get your creatures all to level 40 (in which case, especially as a VIP, you won’t be able to collect all creatures)?
I ask all that because once you decide that, you can decide how you want to play. I originally wanted to get every creature and get each creature to level 40. That’s not a sustainable goal unless you pay real money in. So now my goal is to collect each creature in order of DNA cost and get each creature to level 40. I’ve been playing for two years now, and I am at the Dunkleosteus, if that gives you any clue. Now, along the way, I’ve made a lot of the hybrids as they become available (if a creature is part of a hybrid, I get two of them to level 40; when I get the second creature in the hybrid to level 40, than I make the hybrid).
When there is a discount on (e.g., hybrid dinosaurs 15% off), I’ll buy the highest ferocity creature I can afford. This tactic has allowed me to be fairly competitive in the arena. It was a little over a year before I finished in Dominator. Now I consistently finish in the 60s in Dominator (two years in).
I tell you all that not to bore you (though I probably did) but to give you one way to play the game. There are hundreds of others.
To answer your specific questions, it’s always a good idea to maximize coin production, though you’ll probably eventually get to where you have way more than you need.
As for trade harbor, when you get to having max coins, it’s great to buy loads of Apatosaurus fossils; they give you the best trades. When I get to max coins, I load up on 50-some Apatosaurus fossils, which usually last me close to a month before I trade them all away.
I hope all that makes some sense.
Short version if tl;dr: decide what your goal is, and play in order to achieve that goal. Most important: have fun. Freemium games can frustrate you quick (their goal is kind of to get you to where you pay money to advance, especially by paying to shorten hatching and fusion times). If you’re frustrated, decide what you can do that would not be frustrating.