You need to have a list by room of everything you want and the size and placement of each. You need to understand where your cabinetry will be, measure it out and draw it on the floor so you know if any ceiling joists are going to be in the way of light placement and you can make changes now. You need to specifically talk through all of the kitchen backsplash electrical decisions and placement and any electrical in an island. Make sure your outlets and switches will not be right at the edge of a countertop where you can't get the backsplash installed correctly. You need to know where you plan to put tv's and make sure electrical and other needed cables are in the right spot so you don't have wires hanging all over the place when you move in and install your tv's. You need to know where you want routers and any other cables you need for internet, etc. Personally, i would request an extra dedicated circuit for outlets in the kitchen so that you could use food warming trays and such if you have family gatherings. I would also ask that the garage oulets be on a separate circuit. You would want several exterior outlets and i would ask that those be on a separate circuit as well so you have the option in the future for landscape lighting or electrical for an outdoor patio, etc. The electriciian will tell you that you don't need separate circuits, but there are issues all the time with tripping breakers when all these areas are on the same circuit.

Ask that the electrician and the builder do a detailed walkthrough with you once the roughin is done and go over room by room what was actually done vs what you asked for. Make any changes then before roughin inspection is signed off. Once you sign off, any changes you pay for.