Step 1 - Fix the soil. May need to bring in topsoil or heavily amend. Healthy lawn needs very healthy, living soil.
Step 2 - establish irrigation as needed.
Step 3 - Rid the area of all weeds before planting. This may take time as products to kill weeks need to dissipate before planting.
Step 4 - Grade the surface to ensure good drainage - no low spots for puddles.
step 5 - plant (or sod) , fertilize, and stay on top of weeds
Step 6 - maintain healthy soil for the lawn. Avoid Lowe’s Depot chemical fertilizers. Weed and Feed is not compatible with grass seed as it hinders germination and kills sprouting seed. This stuff is a short term band-aid at best.
If you done the above very well, you’ll have very few, if any, weeds. This time of year a few pop up occasionally. Hand pull them - I had to pull 3 weeds this week.
Don’t cut it short. Most grass blends are TALL blends, yet many try and mow short like a putting green. I keep the mower on the tallest settings as mowing short weakens the grass and opens the door for burned / dead spots and more weeds. Don’t water at night as it encourages fungus - dawn hours are best.