The number one piece of advice from experienced parents: buy less than you think. Babies grow incredibly fast and people love giving clothes as gifts. Focus on practical basics in a few key sizes.
Sleepsuits with zips, not poppers, that is the single best clothing tip anyone will give you. Buy 6-8, split between newborn and 0-3 months. Invest in a Merino Kids sleeping bag if you can, they are the ones our own children sleep in, and because merino works across all seasons it actually saves money versus buying separate tog bags, though a budget all-cotton bag does the job too. Stock up on large muslins, and resist buying tiny shoes, they are adorable but completely unnecessary until baby is walking.
Start with 6-8 sleepsuits (mix of newborn and 0-3 months), 6-8 bodysuits, 8-10 muslins, 2-3 hats, and 2 sleeping bags. Some babies skip newborn size entirely, so do not overbuy in one size.
It depends on room temperature. A merino wool sleeping bag like the Merino Kids Go Go Bag naturally regulates temperature across seasons, replacing the need for separate 0.5, 1.0, and 2.5 tog bags.
Yes. The Lullaby Trust recommends sleeping bags over loose blankets, duvets, or pillows in the cot. Keep the room between 16 and 20 degrees Celsius. A good rule of thumb: baby wears one more layer than you would.