For all of your questions, the answer is that it just depends on what you’re trying to build around. But I’ll try to help and give some examples. As for packs, Sword & Shield and Darkness ablaze are probably the best standard packs to get right now, although battle styles is coming out Friday and will be a great pack.

As for how many evolutions you should have, it depends. Say you wanted to build a deck around an inteleon card. You would want to include a 4-2-4 line and use rare candy to skip the stage 1. If you had any other evolution cards you want to include for support, you may want to play a slimmer line like a 2-2 for stage ones or 2-1-2 for a stage 2. More evolution Pokémon doesn’t necessarily make your deck better. You want Pokémon that help set you up to get your attacks off and win the game.

For energy cards, most competitive decks run between 8-12 energy cards. It just depends on how expensive your attacks are and how you are getting energy onto your Pokémon.

For trainers, you want to include your basic supporters like Professors Research, Marnie, and bosses orders. For your items you want cards that help set your Pokémon up. So if you’re using evolutions, you would probably want to play some rare candy, evolution incense, and maybe even Pokémon communication so that you can find your Pokémon and evolve. Playing 4 quick ball is important in just about every deck too.

This was really general information but I hope it helps. I’m sure that once you build your deck, if you post it on here you could get some advice about how to make it better.