There are 15 months between my two. Routine and Cbeebies are your friend!
It gets loads better once the youngest can sit un aided, then even better again when they can move around on their own.
The youngest will just fit around your routine with your eldest.
I second the advice of treating them like twins. They get bathed, changed, fed, dressed all at the same time.
My husband helps out alot in the morning. I make sure I have a shower every day so I feel better and when Im doing this he gets them ready, changes their nappy and puts the empty bottles in to soak. Just those few things help out loads.
We try to go out every day, even if its just to Tesco Express or the local shops. My tandem pram is a god send as its much easier to get around than a side by side double buggy.
One of the hardest aspects is that you cant leave the 2 in the same room ever so I have loads of double up equipment, 1 of each upstairs and downstairs - 2 bouncers, playmats, changing mats, nappy boxes etc etc. I have 10+ bottles because I havent got the time to steralise and wash them during the day.
My eldest does get jealous of DD sometimes, so I make sure she has pink and purple bottles that he knows are hers and her own plate and cutlery to use.
My mum would also help me out in the early days and take DS off for half a day so I would have some quality bonding time with baby DD or vise versa. That really helped.
I do housework in 15 minute spirts and wizz around when they are both in their high chairs. I dont iron or dust anymore!
I BLW as well - so much easier and they both just help themselves to food off one big plate!
I try my hardest not to moan at DS all the time because I know he doesnt know his own strength and he doesnt mean to hurt baby DD but I find this sooo hard. There are times where they drive me bonkers.
Now they are 10 and 25 months its getting easier and they are starting to play with each other. They love each other so much it melts your heart. Every morning when DS wakes up the first thing he says is "where's baby?"
Good luck OP!