A couple of things…
First, do you have Carnoraptor unlocked? If so, invest in 4-5 Level 20 Carnoraptors if you can. Carnoraptors are very powerful, and completely destroy in Dominator League. Level 20 Carnoraptors have less ferocity than I-Rex G1, so they won’t mess up your lineup or PVEs too much. Once I get two more Pyroraptors, I will by starting this project myself.
Second, work on getting your legendaries to level 40. You should have at least 2-3 level 40’s for each class, or level 30’s for tournament legendaries. These will help with PVEs and can act as backups to your main creatures in Dominator battles. So, if you have a level 20 Carnoraptor as your main and your opponent has a strong amphibian, you can send in something like Pteranodon to deal with it.
Third, work towards getting a level 40 Diplotator and several Tapejalosaurs. Diplotator currently has one of the best superhybrids in the game, Diplosuchus. Diplosuchus is essential for Tournament runs, as several JWTG forum members can tell you. Tapejalosaurus is similar, it creates the superhybrid Tapejalocephalus, another very good hybrid that is very important for Dominator battles. However, unlike Diplotator, Tapejalosaurus is also very good on it’s own. It was the budget hybrid before superhybrids were introduced. Just like Carnoraptor, I’d work on getting 4-5 level 20 Tapejalosaurs.
Fourth, do modded PVP whenever you can. If you can get into the Elite tier of modded PVP, you are guaranteed decent prizes, with no food or coin. You can win bucks, DNA, and S-DNA in modded, and sometimes you can even win good creatures like Spinoraptor and Rajastega.
Hope this helps!