Disciplining a 2 year old

[PeppaPrig]

I love the idea of UP/AP. I try to keep 2yo dd not overtired or hungry, remove things I don't want her to play with, explain why she can't do/have something, say 'no' and remove her. But the boundary-pushing is going up a notch (about to turn 2) as are the tantrums, and I find myself turning into shouty mummy which I hate.
Would the naughty step work better? And how does it work? Or what else do I do?
Flash points are boredom and perhaps jealousy, as it gets worse when I'm feeding newborn ds. Things I find unacceptable are jumping on the sofa, playing with the blinds, hitting me, throwing. All standard toddler fare, I know, but I don't want her to do it!

We use the naughty spot with our 2 year old and we've been using some variation of it since she was 1. That may sound harsh but she really gets it now and also has known her boundaries for a long time.
If my DD is doing something I don't want her doing eg jumping on furniture etc I ask her nicely to stop it, if she doesn't I say I'm going to count to 3 and if she doesn't stop Mummy's not going to be happy. If she doesn't stop then I get down to her level and say mummy said no, this is your warning do it again and you're going into time out. Then if she carries on I pick her up and move her to where there are no distractions and with eye contact say You are going into time out because of xyz, you will sit here for 2 minutes.
This is the bit that may take her a bit of time to get used to as she will try and escape but they do get it if you keep on returning them to the spot.
As my daughter has got older she will stop most things now on the count to 3 and I very rarely get to the time out.
If my DD hits I take her straight into time out because she knows that is completely unacceptable.
The aspect of your issue I can't advise on is when you are feeding your newborn as I only have the one. However, have you tried reading her a book while you're feeding...don't if that will work but it was a thought I had when I was thinking about if we were to have another!
Hope that's been of some help.

I started using the 'naughty mat' with ds when he was 2 and it has worked brilliantly, far better than I expected. They stay on it for a minute per year of their age. You warn them before, as above, to stop doing whatever it is they are doing or else they'll go on the naughty spot, or for something very bad like hitting you just put them straight on it. At the end of the 2 minutes you explain why you put them on it (briefly) and get them to say sorry, then we have a hug. Ds is now 4yo and the threat of it still works. I also have a 12 week old baby and agree it is hard while feeding. I try to curb tv at other times but am more likely to let him watch cbeebies when I'm feeding, to make life easier.