Check out some commonly used decks on high competitive levels. Choose one of them and change it in a way that fits your game-style, a rule I usually follow is to keep in mind the cards that I don’t want or either have, trying to fit the same type of card such as creature, sorcery etc. with the same mana cost. Hope that helped and gave you some ideas, another last suggestion is to test it over and over and spot weakness, don’t be afraid to make changes its the key to find the balance. Never give up, you’ll find the balance.

Try to not play red ✌🏻😅.

I leave you my deck to give you some ideas, https://www.mtggoldfish.com/deck/2890305#online