First pick a theme that feels natural to you – maybe a combo that wins early or a control deck that turns the tide. Then make sure every card has a purpose: either it supports the main win condition, it keeps the opponent in check, or it gives you a card advantage. Keep the mana curve balanced so you never stall; a couple of low‑cost spells, a handful of mid‑range minions, and a big finisher is a solid pattern. Watch the synergy – if you have a spell that triggers every time a minion dies, pair it with a discard or death‑rattle card. Add removal that fits the deck’s tempo, not just random trash. And don’t forget to include a few cheap ways to counter the opponent’s early threats, so you can maintain control. Finally, practice your deck in low‑stakes games first. Notice where you lose control, where you’re forced to play extra cards, and adjust. A patient, methodical approach will let you outplay anyone who rushes too hard.