A lot of new players have started playing Gods Unchained recently. The launch of the Play to Earn mechanics of the game through implementation of the $GODS token and re-opening of The Forge which enabled players mint their cards and sell it to the market -- has attracted new users from all over the world.
It seems the game has progressed a lot from the time I started playing and I felt a bit nostalgic that made me think of what I wished someone could have told me when I started playing Gods Unchained.
The Gentle Art of Mulligan
How you Mulligan (picking your starting hand) can win or lose you a game. There's a lot of intricacies of doing the Mulligan depending on the deck you are playing and the archetype you're playing against. So there's not really an exact way to tell what or how to do your Mulligan as that's something you will have to learn by putting in the time in playing your deck of cards.
But if there is ever a hard rule about the Mulligan is that if you're playing second, you should not mulligan like you're playing first. So generally, having three pips of bag of tricks (or extra mana) when going second will enable you to play higher mana cards. So instead of having 1 or 2 mana cost cards in hand when going first, you can opt in holding cards that are 2, 3, 4 range when going second.
Also, you might want to Mulligan for more reactive cards that will help you regain board control or counter the usual initial drops of your opponent. These might be an over simplified guide but this helped me to win more games and wished I could have known this sooner.
Bad cards vs Good cards
Learning which cards to put in you're deck is one of the skills you should learn as early as you can. Even if you're on a tight budget, there's a lot of quality cards out there that you will be able to own at a small cost. You can research at GUDecks to check which cards can give you a better chance on winning just by looking at the winning percentage of the cards and how often they appear in constructed decks.
Watch the best players' stream on Twitch.
Just watching the top players like 
I had a very hard time reaching mythic when I was a new player then I started watching their streams and that's what helped me correct some of my misplays that finally enabled me to elevate my game and reach Mythic rank -- which lead me to my next realization:
Don't be afraid to get your arse kicked in Mythic Ranks
You will hear/see other player's say that it's not worth leveling up to Mythic when you are a F2P (free to play) player and that it's better for you to stay in the lower ranks because it's the easiest path on obtaining Weekend Reward packs. That's not completely true (or even ethical). If you are able to reach Mythic, try your best to stay and compete in that level with whatever cards you have. It will be better for your growth as a player in the long run.
Like the old saying goes: "If you are the smartest person in the room, you are in the wrong room" and that old cliche "Iron sharpens iron" -- those things are very true in this game. You can only be better by competing with top players.
Hopefully, new players will be able to read this and help them navigate their way to Mythic Ranks and win more consistently in the weekend rewards.
May the mulligans be in your favor!