I would:
Worry a LOT less about making breastfeeding work, and feel less guilty about topping up as needed
Start with second hand stuff. Pushchair chosen for ease of handling/grappling on and off buses, not looks. Baby clothes plentiful, comfy and not remotely special - they're going to get covered in shit and puke anyway
Co-sleep and feed/cuddle to sleep without feeling guilty with my mother's "rod for your own back" narrative ringing in my ears. She was wrong. I wish I'd enjoyed it more.
Tell the HV to do one, at the first sign of battiness or rotten advice. I know there are great ones out there, but Christ I met some fruit loops.
I would NOT:
Go to baby groups, toddler groups or any other "class" which involves horrible local mum politics, parents sitting in a circle singing while the kids ignore them, humping play equipment around at the end while nobody else helps, etc. Sod that for a barrel of bananas. Babies don't need it and I hated it.
Let anyone take the baby off me when I didn't want them to. Grabby relatives made me really uncomfortable, and it's only in middle age that I've acquired the ability to say "No, I think not, actually."
Feel the slightest embarrassment about breastfeeding in public. I was so cowed by the odd nasty/judgemental comment, it was crippling. Now I'm a grumpy old cow and I couldn't give a witch's tit what anyone thinks about me.
Puree shit and freeze it in ice cube trays and all that jazz. It was all so unnecessary and time-consuming.
Anyone else?