What's the first component you start with when picking out an outfit?

Depends on the day. Sometimes I feel like wearing a certain item. And sometimes the weather decides -- lately it's been so hot that I'm inclined toward my coolest stuff.

Same as Doc. But you know what - I only have a few jackets/suits that I rotate through, so the first consideration is the jacket.

Dress shirt normally. Occasionally I'll base it around a tie though.

Pretty much the same as Doc. Sometimes I have new shirt that I want to wear, so I build around that. Today, I wanted to wear a new PS, so I went super basic for everything else after picking the square.

Most often, its whatever I bought the day prior.

I also concur with Doc. In cooler weather I usually start with a jacket selection and work from there
Welcome to Styleforum Mr Engineer.

That's baller talk.

Suit first...
Shoes/socks.
Shirt and tie to complete...

Sometimes shirt. Other times tie. Still other times shoes. All depends on how fat I'm feeling that day.

Suit first, whichever comes up next in the rotation. Or if it's a blazer day, then that. Almost all my shirts are blue anyway, so picking that is simple. Shoes are more about style than color, since they're all black or brown. And the tie comes last, especially as I get more and more solids in my collection.

The square is the only thing I leave up to whimsy.

Shoe/Pant combo
Jacket
Shirt
Tie
Socks

If I am wearing a suit, then of course I pick the suit first

 

Yep, same here. It's day-dependent rather than a definite routine.

 

The one thing I'd add is that when I have time, I lay out a few different outfits, chopping and changing items between them to find a combination I like. This takes about 5 or so minutes to settle on a combination so I don't do this every day, but when I do, I'm invariably more pleased with the final result than when I just match on the fly. If you have a more efficient wardrobe than I, then obviously this step is unnecessary as most of what you own will tend to pair well enough with everything else (assuming you applied thought when buying/ordering).

From the list:
Jacket (+ Tie if applicable)
Trousers
Shoes (& Socks)
Shirt
Pocket square