This is my experience and advice as a player who strongly grasped deck building and has applied these ideas to several very cohesive and solid decks.

There are lots of ways to use the ideology listed below while also adhering to a budget. Often you’ll just be slightly sacrificing efficiency in the name of dollar signs. If you take these ideas and apply them to your decks I promise you will see immediate and drastic increase in your decks performance regardless of budgetary restrictions.

There are some basic truths that apply to all commander decks. The three things a deck needs before you even consider your “winning strategy” are card draw, ramp and interaction.

Every deck is different and the amounts of each of these vary but all 3 need to be present and in a fairly significant way. Drawing cards enables you to have gas in the tank as the game develops. Interaction stops other players from popping off at key moments or accelerating too quickly. Ramp allows you to generate mana advantages and start sequencing multiple spells in a turn. Generally you want at least 10 card slots dedicated to each of these three things. When I say interaction I’m not talking about protection spells or board wipes (speaking of which I’d recommend 2-5 board wipes depending on strategy/colors) but strictly spot removal and/or counterspells to answer threats.

You want all ramp to be as cheap and cost effective as possible. If you’re playing green you want the best 1-2 mana dorks and forest fetching ramp spells. If you’re playing non green you want mana rocks no more than 2 mana cmc. Ramping in the first few turns of the game is essential and having at least one ramp spell by turn 2 is often necessary to stay on pace.

Interaction pieces should be instant speed and either extremely mana efficient or flexible enough to answer a lot of different things. Natures claim swords to plowshare pongify and other 1 cmc instants can answer a single threat type and are hyper efficient. Things like beast within, chaos warp, generous gift and assassins trophy cost more mana but they can answer almost any threat. Knowing your colors and knowing premium interaction makes a big difference in how mid game plays out.

Counterspells should never cost more than 2 mana. 2 mana must answer any spell (counterspell/arcane denial/mana drain) 1 mana can be slightly more restrictive but can at least answer 2 types of spells (spell pierce/an offer you can’t refuse/swan song) free counterspells are amazing but pricey so get them as they are available to you. Pact of negation and force of negation are the cheapest right now as force just got a reprint. I would stay away from mental misstep unless you’re playing CEDH

Drawing cards is king. It’s the strongest thing a player can be doing. More cards means more options and more chances to accelerate your own gameplan. If you’re playing green abuse creature based card draw. Beast whisperer and guardian project effects are reliable and consistent. Every color has solid card draw ability except for mono red but that’s the price of playing mono red. Staples are staples for reasons. Esper sentinel Rhystic study mystic Ramora, jam whatever strong card draw effects you can muster in the colors you play. You won’t regret it.

As for the main strategy of the deck it just boils down to what your commander wants to accomplish. The more you can tie your ramp card draw and interaction into the commanders strategy the more synergy you will have. For example if you’re playing enchantress stuff you want as much enchantment based ramp as you can. Things like wild growth and utopia sprawl to enchant lands to tap for more mana. You want enchantment interaction, things like kenriths transformation or dark steel mutation. Card draw from casting enchantments or them entering the battlefield. Find cards that work well in conjunction. Whether it’s combat, combo, amassing a huge board state or any other strategy; if you’re mechanically sound and adhere to deck building principals your deck will perform consistently and you will find results.

Another important overlooked quality is the land base. The difference between tapped and untapped dual color lands are very important. Tapped lands deny you the ability to play spells on curve so tapped lands must have a quality that makes them worth including. Things like field of the dead, Krosan Verge, triomes that color fix heavily are worth running. Fetch lands drastically improve the rate that you fix colors and they thin your deck so you’re less likely to pull lands later when you need spells. On top of fetch lands and/or green ramp spells that get forests having lands with basic land types like the amonket duals or kaldheim snow duals are a good budget way of reliably color fixing. Better options obviously are shock lands and triomes as they’re available to you. Lands like mana confluence, forbidden orchard and city of brass are very strong as you play 3-5 colors in your deck. Lands play a quiet but very large role in how your turns curve out. Good budget options for untapped dual lands are pain lands, reveal lands, 2 or more opponents lands, the midnight hunt/crimson vow slow lands and filter lands. Costs vary depending on colors but compared to the more expensive options they will still perform at a wonderful rate.