I think the key advice is to do what is right for YOUR little family - you, baby and your partner/spouse if you have one.
Weirdly it was my very toxic dad that gave me that advice! He said loads of people will give you unsolicited and utterly bonkers advice - say thanks, smile and then do what YOU think is right
My mum (usually much less overtly toxic) was the one criticising almost every choice I made (and even some things I had no choice in! Like the emcs "oh could you not cope with a normal birth" even though she knows baby's and I's lives were at risk!) breastfeeding, swaddling, dummies, naps, feeding to sleep... she criticised the lot!
I just cracked on and did what suited dd, me and my then husband.
Some of her advice directly contradicted safety advice like cot death guidelines! Maddening
Anyway...
Also op I was a nanny before having dd and I STILL freaked at the responsibility. There are certain things you never do as a nanny as of course they happen either very very early in baby's life (belly button nonsense totally threw me!) or you're working set hours so you're not dealing with night wakings etc (and are getting a decent amount of uninterrupted sleep!)!
One step at a time, ask for advice from those you trust and on here and nhs sites etc
Agree with pps that "rod for your own back" in first few years is total nonsense! All babies are different, some will learn to sleep through quickly, others take a while. I've certainly come across smug first time parents who reckon they've cracked baby care and are natural experts - only for no 2 or even 3 or 4 prove them completely wrong!
I had my own ideas, I was going to be a laid back, non routine led mum... what I got was a baby that CRAVED and needed routine (turned out I learned much much later that dd has a disability and many of the effects are minimised by good routines in certain areas - eg eating she's prone to stomach upsets because of it and needs to eat little and often BUT at regular times), if she was late down for a nap she was MURDER for several days after for not sleeping well at night and being an overtired cranky mess! So I learned the hard way she had to have her routine. She's now 20 and is still the same!
@Vursayles is right - a regular clear out of all the stuff they accumulate is good. I used to do this quarterly (seasonal change good time to pass clothes etc on) to keep on top of things.
Buy clothes for the next stages up in advance in the sales! Well worth it
Yep! I did this too. I was a single mum on a low income from dd was quite young and I never paid full price for a winter coat until she hit fussy high school stage. I'd buy next winters coat in the Easter sales some for less than £5 and brand new!
We also co-slept safely until around 3 months meant we all got much better sleep. I was bf at this point and it was so much easier to just pop baby on to feed and us both stay cosy in bed.
It is not the time for it! Your only aim should be to make it through the day in one piece.
Totally agree! I lived in pj bottoms or leggings and a dressing gown first few weeks, dressing gown just to quickly make myself "decent" if guests appeared.
Breastfeeding is a skill you and baby both have to learn - it takes a while. But once you crack it personally I found it very convenient. My milk dried around the 9.5 month mark due to a medical issue which led to a bit of a flap! Ff I personally hated, found it a total pain in the arse! So much faff and bottles once made up don't last long especially if you leave the house, with bf none of that worry you're very mobile, ff you have to remember to take all the kit, how long bottles been made up, maybe need to find somewhere to get it heated up...faff! At the time I lived a 45 min drive from my nearest decent shopping town so I had to time trips there very carefully BUT it's a very personal decision some love ff and find it easier pros and cons to both
Regarding partners - baby doesn't necessarily want the same from them as they want from you. Eg my dd wanted me to hold and rock and settle her one way and wanted her dad to do something totally different - took us a while and observation from ex's mum to spot that one. Your partner will have a different relationship with your child. I was calm and cuddles, dad was physical and playful eg one thing my ex did when we were together was did his morning exercise with dd "incorporated" into them he used her as a sort of weight sounds weird she loved it! BUT she hated me trying to do anything similar with her. She also ate solids better for my ex than me no idea why.
This may sound strange, and it may just be me but after giving birth my centre of gravity changed
That's normal, your weight and distribution of weight have completely changed overnight! I crashed my side into a door frame the day I first stood up, my mum face planted after having me! Bust her lips up!
Also op your body is PERMANENTLY changed, it's not just fat/weight, it's also muscles and bones and joints, they all alter to accommodate the pregnancy and birth that's why on tv crime shows they can tell from a skeleton a woman has given birth - the shape and angle and make up of the pelvis changes
Music with a heavy base helps colic - weird but true! Dd now a huge fan of GNR! 
Just remembered to say - my dd was v poorly at first and tube fed and then ff in hospital but it is possible to change to bf from this I did it, first midwife I saw at home said it wasn't possible but 2nd said it absolutely was and helped a lot she had a lot more experience with poorly babies than the other one. It was important to me as lots of allergies in the family and bf can really help with that. Dd has some allergies but nowhere near as many as the rest of us and much more mild in severity so I'm glad I did that
I wasn't able to have more than one so I envy all who were. Enjoy this time it goes by in a flash.
As I say my dd is 20 and left home now and I'm wondering where the time went!
Good luck with it all