To add on to that, I’d say it’d be good to understand deck archetypes to give you a base to start building from; namely Aggro, Tempo, Midrange, and Control.
Aggro decks are trying to end the game as quickly as possible by being as aggressive as possible. These decks typically want to put down the most cost/power efficient creatures in their colors every turn, and turn them sideways. Versatile burn spells (meaning spells that can deal damage to creatures and players,) are also a mainstay of these decks, to remove early blockers and send damage to the face. Red Deck Wins is a type of monored aggro deck that is dead simple as far as individual card complexity goes and works off these types of cards.
Tempo decks are somewhat nebulous by definition but can be defined generally as decks that are both aggressive and disruptive, and win by maintaining “tempo.” Individually the cards in tempo decks are not the strongest available but when working in conjunction with one another to disrupt an opponents’ gameplan while putting on pressure they do a lot of work. Tempo decks often pack small evasive creatures, and lots of cheap ways to disrupt your opponent, i.e. targeted discard, bounce effects (effects that send something from the battlefield back to the opponent’s hand.) These decks have a high level of synergy between most of their cards. Some of them have enough disruptive elements to play a more control-style game as well. UW (Blue White) Spirits is an example of a tempo deck.
Midrange decks are built off the backs of individually strong cards, to the extent that winning with a midrange deck is described as a process of meeting your opponent “card for card.” Synergy and aggression take a back seat to playing deal-with-this-or-die creatures, removal (often with additional upsides tacked on,) and any card that can generically generate value by itself. An iconic midrange card would be Thragtusk, which provides a ridiculous amount of value off a single cast by giving you a 5/3 which will either do a ton of damage or force a bad trade, 5 life, and a 3/3 token to replace it once it dies. Grixis Midrange is a powerful deck that’s in Standard currently.
Control decks are about controlling the game. They tend to have 1 or 2 very expensive cards that will win them the game, and are otherwise about making sure your opponent can do as little as possible. You almost never play spells on your on turn and are entirely reactive as a deck. Winning is a matter of spending your removal, counterspells, and discard spells at the right time on the right threats, and then dropping a bomb of some kind once you’ve stabilized and your opponent is running on a quarter tank. Esper Control is a control deck in Standard right now that wins off of Torrential Gearhulk.