Ah - a subject close to my heart! 
My dd1 is 20 months and my dd2 is 18 weeks - a gap of 16 months!
I thought it was going to be a nightmare - but it isn't as bad as I thought. I'm lucky in that dd1 goes to nursery 3 days a week.
I had to have a c-section with dd2 so dd1 was booked into nursery full-time for a month otherwise I wouldn't have coped as dd1 wasn't walking properly and I wouldn't have been able to pick her up etc - I know I am lucky to have this flexibility.
Luckily, dd1 is too young for the sibling rivalry but there can be a bit of jealousy but also a lot of affection for her little sis. 
Also, (if relevant to you) bf didn't go as planned with dd1 but is going well with dd2 -well chuffed! 
There are other postings on this subject (but I was always rubbish in finding things in the archive). If you have questions or requests for advice - post as I'm sure you'll get lots of responses. 
My tips/what I did.
I moved dd1 from her bedroom well in advance of dd2 coming so she didn't link the being moved from her room and the addition of the new baby.
I also moved dd1 into the new pushchair (I got a Phil & Ted E3 Explorer which can be used as a single and a double.)
I asked the nursery to minimise any disruption around the birth of dd2 - hence dd1 moved classes slightly early.
DD1 had a pressie from dd2 in the hosp (a Fifi Flowertot doll)
HTH 