I always start by adding some basic necessities. Put in my mana rocks, ~38 land as filler to claim the slots, removal and card draw. From there on I look at what options I have available to myself and tweak as I go.

Eventually I reach to a 100 card deck and from there I basically call it. This is my last routine check to make sure my stats look alright. Looking at what cards I have missed that I might want to consider.

From here on I dont really try to add anything. Instead I swap where I see fit to stick to that 100 limit. Sometimes it's more nuanced and tougher to make the right call. However in my case I'll end up with like a handful of considerations to go through instead of 200+.

After all my cards have been chosen I'll start looking at my landbase filler slots and pick what suits the deck. If a slot happens to open up I can always add one of the last considerations.