Things noone told me (but which I figured out, using the principle that nature can't be entirely stupid):
That it is entirely normal for babies to cry a lot/ stay on the boob for hours when a few days old. This is because they want your milk to come in. Just keep feeding (and ignore the midwives mutterings about bottles) and your milk will arrive. The baby will not starve in the interim!
A big baby is not hungrier and does not need top ups because your milk is not in on day two. Nor will a baby die who doesn't feed in the couple of hours after birth. I know number of women who have given bottles (on mw advice) to stop their baby crying on pn wards, and then not bf much thereafter. Which if fine, if they wanted to bottle feed, but the advice that they must top up an 8 pound baby is wrong.
That tiny babies are ruled by their digestive systems. They get hungry, this makes them frustrated. It oesn't occur to them that it is hard to latch when they are screaming. Cuddles and and skin to skin can be the remedy for this.
Sometimes babies just cry. But in the first few weeks it is a good idea to put baby to the breast whenever it cries as this is great for your milk supply.
That babies often prefer one boob to the other. I have a slightly inverted nipple which my two did not like. So they always got that one first so that I didn't get lopsided. When I was very engorged it was harder to latch them on this side so I used an ice cube to pop it up.
At about 14 weeks or so it is fine to no longer feel engorged so much. Your milk is still there.
Breastfed babies can go ages (a couple of weeks even) without pooing after 6 weeks or so.. They don't need orange juice, however much well meaning neighbours recommend it.
Breastfeeding has a psychological element so relax and trust nature and your milk will come. New babies can even drag themselves to your nipple and latch! My DD1 did not feed until several hours after birth when she suddenly did this as I was keeping her in my nightie top!
Breastfeeding can be sore (in which case get your latch and your baby's mouth looked at) but it can be entirely painless and lovely too.
This boils down to: just keep feeding, and it will come good.