In my experience I suggest this:
Firstly, think in the long run, what is your goal? Mine was getting into tournaments in dominator, it will take you a lot of time but by the end it will be worth it.
2-Make all the free Dinos you won, and start focusing in building slowly a team of legendaries, this team will help you latter so you can start with a level 20 and then with luck gain another two and start having teams.
3-Always have balanced team, my recommendation is that all of your 12 first creatures have the same ferocity level, this will help you winning all the events.
4-Do all of the events you can, and all of the missions so you can progress.
5-Once you progress a lot you can sell useless Dinos for DNA and use that DNA for improving your upper team.
6-Once you unlock trade harbor you will use apatosaurus fossil to dinobucks (you will get 1-3 trades a day), with this 300-400 dinobucks do moded pvp using one legendary level 40, and two low level creatures, by this you will gain sDNA for cool hybrids, some nice dna providing legendaries, and even spinoraptor, me after 2 months of daily having 5 fights with only level 40 legendaries ended winning 1 Rajastega, 2 spinoraptors, 8 diplotators and like 40 nice Dinos legendaries/súper rares that i traded for a lot of dna, do it only with trade harbor unlocked and with one legendary 40 per team.
Finally, SAVE,INVEST, REPEAT… save all of the LP you can to get 10k VIP packs, this will help you a lot, and start focusing each dino not thinking in today but in your future needs, it might take you 1-2 months to build a good team and level up but it’s totally worth it!