First time round it's easy to get sucked into buying lots of stuff and then you realise you don't need half of it. Clothes wise, dd was dressed in babygros/bodysuits for months on end. I knitted some cardigans and jumpers to go over the top but honestly multipacks of babygros and bodysuits were all we needed. All the hat, booties, socks, bonnet fripperies were just a nonsense. We also then had something warm for travelling in (like a pram suit), blankets, several of for layering.
Then... somewhere for the baby to sleep, a way of transporting it (sling, pushchair, carseat etc, whatever you choose) and paraphernalia for cleaning them (nappies, wipes, cotton wool and 8 million muslins/bibs). If you're ffing or expressing, obviously you need to think about bottles and gubbins too.
That was pretty much it. People will buy stuff and if you're canny and they ask what you would like, you can ask for the other non-essentials as gifts. Things like a baby gym or bouncy chair but again, you don't need these for a newborn anyway.