Stick to the planed material as originally specified and quoted. Watch the scope creep and urge to upgrade during construction.

Right. You get more bling for the buck if you just go to Toll Bros.

I would:

Pay more attention to energy efficiency and comfort. This would cost more and also impact design.

I would have put in another half bath.

I would eliminate exterior doors out of the laundry room and garage.

I would have budgeted for exterior hardscape and landscape as part of the whole process. Not "save money" by doing it later.

I would have another larger linen closet upstairs.

I would do all the floors the same high quality. Not "settle" in the non-public areas.

Adding...all of this would have impacted square footage and "architecture." That is...less bling for the buck.

What is your expectation of "custom home?"

Avoid project creep, or at least recognize and admit it when it happens.

Time is money. Assuming you have a current mortgage and will pay interest on a construction loan during your build, achieving an on-schedule completion is important to stay on budget. Select a builder who has a proven track record of delivering homes on time.

@User Ouch!! What reason did they give for that? Do materials cost more?

Absolutely!!! There was a shortage in lumber and many other material. Then there is the appliance shortage. When Covid shut down the world the first time, many manufacturers closed down. For those stuck at home, many people started DYI projects. Supply went down and demand went up.
Pricing goes up.

Second JJ for designing, budgeting and doing exterior hardscape and landscape. Everyone on the same page re: the high cost items at a minimum (windows, floors, interior doors, trim, bathroom finish, kitchen cabinets, appliances) before construction starts. Become familiar with cost of plumbing fixtures and lighting you can live with as well. You aren’t going to “save” once you get started - the estimate is only going up. Particularly with COVID.

Sit down and think about what is important to you and where you want to upgrade and where you don't.

I just finished a custom build.

I found a solid hardwood floor in a stain I liked that is 4" wide. I decided I'd be happy with the narrower plank and did not upgrade the wood floors. However I did pick out more expensive cabinet pulls that I love. Another example, I splurged on a Wolf cooktop, but bought Bosch fridge and dw.

Try to ensure the floorplan, roofline are an efficient use of space with less wasted in halls, etc.

There are beautiful choices in porcelain tile today so use these for your master bath.

I personally like natural stone. Look through granites before you decide you need to go with quartz which is often costlier.

Bigger isn't necessarily better. Build to the room sizes and proportions that work for you. If you build something huge and you don't need the space, you'll pay more for building, furnishing, heating and cooling.

Start with a talented architect unless you are a designer with design skills. Even then I highly recommend running it by an architect. We as non professionals don't know what we don't know and in the long run while it sounds counter intuitive, a talented architect will save you money.

Put together a list of your must haves, wouldn't it be nice to haves, and in my wildest dreams maybe I'd like to have and work with your architect to create it. Really think about how you live and not the fantasy of how you think you might want to live if only.

For example, my idea of entertaining is setting out a buffet and everyone coming over and helping themselves and sitting wherever. For small groups, I use my colorful fiesta ware, and for large groups, we do paper plates. However, in my fantasy, I am cooking up duck ala orange with all the trimmings for 10 people and serving it in my gorgeous dining room on specialty china while remaining perfectly dressed with no food spills on me. That's not my reality, so I chose not to have a formal dining room for that reason. It would be wasted space for us.

Get everything decided on BEFORE you build. I mean everything. Windows, doors, flooring, appliances, plumbing, etc.

Make the choices before and don't change your mind after because changes cost money. That also includes changes to the building itself. Don't suddenly decide you want a room opened up, or you suddenly need cased openings when you at first decided to do uncased. Stick to the plan your architect designs. Ask him/her to show you in CAD how you'll walk through your house and how it will look inside.

Plan for a house that is U, L, I, T or H shaped so that you can have windows on at least 2 walls in all public rooms and in the bedrooms. And yes especially in the kitchen. A house with lots of natural light will live better than a dark house.

Spend your money on the important stuff, windows, doors, HVAC, insulation, etc. The things that aren't pretty but will help you to live better. If you have to cut back, do it on the pretties.

Design a house so that you're not walking through the kitchen anytime you need to get to another room or to get from the garage to other rooms in the house. Your kitchen should never be a thoroughfare.

Make sure the house has good flow and a central organizing theme. (This is where a talented architect comes in.)

Lots and lots of closets or built in storage. Figure out what you have and where you want it to go.

If you can, orient your public rooms to face south so you get better passive solar heating/cooling. Avoid kitchens on west walls if at all possible. (You'll thank me for this advice in summer!)

I highly recommend you start by reading The Not So Big House by Sarah Susanka

Get it right the first time and avoid change orders. For some reason, any design changes/additions always add way more $ than if it was reversed and you had the option and deducted it lol

Put together a big list of home design goals. If you don't have a lot of specific goals for a home design, then you're probably better off saving on the expense and headache and buying a home that's already been build (this was our list, as an example).

Have a general idea of what architectural aspects are expensive (generally, the skin of the house is expensive. so are corners and custom windows. the cheapest house to build is a two-story box with no windows. Not a very fun place to live in though).

Plan an efficient floorplan. "Efficient" is different for different people. Pay attention to how you use space. Particularly in your own house. Don't spend money on a 200 sq. ft formal foyer if everybody is going to enter your house through the garage.

Don't change things once you've decided on them. As others have mentioned, changes cost money. The later they come, the more they cost.

Start with your site, and design a custom home that is responsive to it's site. Don't fight your site.

@JJ

You'll get more bling for the buck with tract if you stay basic. As you load them up with extras, tract builders catch up quickly.

Site selection and initial design guidelines are the key.

You’ve gotten some great advice here from some well-respected folks on this site. I would just add to make sure EVERYTHING is covered in your contract, that the contract spells out timelines and timing and conditions of payments. And, as your build goes on, document every conversation in writing to your contractor, and (never OR) to his subs, if your contractor allows (ours did). We had a very honest contractor. It still took us four months to finalize our contract, which probably ended up being thirty pages including all the drawings and schedules. And realistically, everyone forgets things over the course of the build. Most important advice? Keep civil, honest, and reasonable. Things will come up. Good luck!

Btw, our contractor for our first custom build was NOT honest (my excuse is we were quite young), but we ended up with a well built house for thirty years. We were the only people on the street who didn’t sue him. We checked it every day, and he liked my husband:)