I had 3 under 3. My top tips would be:
It gets easier once you get used to the idea that someone is going to have to wait for attention sometimes and a bit of crying (toddler, baby, you!) is inevitable.
Get into doing more than one thing at once. Feed the baby while the toddler is eating breakfast, that kind of thing (Shreddies briefly soaked in milk make good finger food, as does toast). Read the toddler a story or do a jigsaw together while feeding/holding the baby.
Bathtime: run bath, put toddler in. Undress baby and place in plastic seat in bath. Wash baby. Remove baby, dry and dress on mat next to bath. Give baby a quick feed to stop baby screaming. Get toddler out and dry/dress, all pile into your bed where you read toddler story and finish feeding baby. Ideally baby falls asleep and you put them down while you finish story and cuddles with toddler.
If you have a partner have a shower before they go to work (even if you then go straight back to bed
)
Sling. And a decent double pram.
Take the baby to bed with you (safely of course) every afternoon while the toddler naps. After a while baby will get the idea that this is nap time and hey presto you get an hour or two's respite in the afternoon.
Remember that 6-10 weeks is usually the toughest bit of having any baby, whether they are your first or your tenth. It will get easier.
This will all be worth it. Small age gaps are the dogs' nuts.