STOP!!!
Sadly, while you should definitely break open the champagne, hold back with the big spending. A publishing deal doesn't mean you getting the money in one wodge, it's a staggered payment. Plus, your agent is going to be taking a cut from it, 10% or more usually nowadays, 15%. That's £2000 - £3000 gone immediately. You're now playing with £17,000.
This is likely to come in several stages:
1: Signature of contract
2: Acceptance of manuscript
3: Publication of hardback
4: Publication of paperback
There are variations on the stages: if your manuscript is already completed, Stage 1 & 2 are combined so there are only 3 stages; if it's only coming out in hardback or paperback, then again that's down to 3 stages.
So if it's 4 stages, that's £4250 per stage, 3 stages is £6333. Nice money, but it doesn't have the same woo-hoo qualities as £20,000. Especially when it may be spread out over a couple of years.
I signed my deal in October 2002, when I got Stage 1. I had to wait until January 2004 for Stage 2 for hardback publication, and May 2004 for Stage 3. In other words, the money was spread out over 20 months.
Let's suppose you've signed a £40,000, 2 book deal. Woo-hoo! Book A is finished, Book B is just a synopsis. It's October 2011, they've decided the perfect time for your book to be published is April. It takes about a year for a publisher to produce a book so that's not going to be April 2012, but 2013. That means that Book B is scheduled for April 2014. Because Book A is finished, it's on a 3 stage payment. Book B is but a couple of pixels on your laptop, so it's on a 4 stage payment. Here goes...
October 2011: Stage 1 (of 3) signature/delivery Book A = £6333, Stage 1 (of 4) signature Book B = £4250
November 2011: Nothing
December 2011: Nothing
January 2012: Nothing
February 2012: Nothing
March 2012: Nothing
April 2012: Nothing
May 2012: Nothing
June 2012: Nothing
July 2012: Nothing
August 2012: Nothing
September 2012: Nothing
October 2012: Nothing
November 2012: Nothing
December 2012: Stage 2 (of 3) hardback Book A = £6333
January 2013: Nothing
February 2013: Nothing
March 2012: Nothing
April 2013: Stage 3 (of 3) paperback Book A = £6333
May 2013: Nothing
June 2013: Stage 2 (of 4) Delivery of ms for Book B = £4250
July 2013: Nothing
August 2013: Nothing
September 2013: Nothing
October 2013: Nothing
November 2013: Nothing
December 2013: Stage 3 (of 4) hardback Book B = £4250
January 2014: Nothing
February 2014: Nothing
March 2014: Nothing
April 2014: Stage 4 (of 4) paperback Book B = £4250
Hopefully at some point in 2013 you're signing a deal for Book C and Book D, so more money will pitch up then. And other rights sales may help out, as will royalty payments if you get them, and PLR from the libraries. But I hope you can see why people say "Don't give up the day job" when you sign your first deal.
I signed my deal in October 2002, when I got Stage 1. I had to wait until January 2004 for Stage 2 for hardback publication, and May 2004 for Stage 3. In other words, the money was spread out over 20 months.
Let's suppose you've signed a £40,000, 2 book deal. Woo-hoo! Book A is finished, Book B is just a synopsis. It's October 2011, they've decided the perfect time for your book to be published is April. It takes about a year for a publisher to produce a book so that's not going to be April 2012, but 2013. That means that Book B is scheduled for April 2014. Because Book A is finished, it's on a 3 stage payment. Book B is but a couple of pixels on your laptop, so it's on a 4 stage payment. Here goes...
October 2011: Stage 1 (of 3) signature/delivery Book A = £6333, Stage 1 (of 4) signature Book B = £4250
November 2011: Nothing
December 2011: Nothing
January 2012: Nothing
February 2012: Nothing
March 2012: Nothing
April 2012: Nothing
May 2012: Nothing
June 2012: Nothing
July 2012: Nothing
August 2012: Nothing
September 2012: Nothing
October 2012: Nothing
November 2012: Nothing
December 2012: Stage 2 (of 3) hardback Book A = £6333
January 2013: Nothing
February 2013: Nothing
March 2012: Nothing
April 2013: Stage 3 (of 3) paperback Book A = £6333
May 2013: Nothing
June 2013: Stage 2 (of 4) Delivery of ms for Book B = £4250
July 2013: Nothing
August 2013: Nothing
September 2013: Nothing
October 2013: Nothing
November 2013: Nothing
December 2013: Stage 3 (of 4) hardback Book B = £4250
January 2014: Nothing
February 2014: Nothing
March 2014: Nothing
April 2014: Stage 4 (of 4) paperback Book B = £4250
Hopefully at some point in 2013 you're signing a deal for Book C and Book D, so more money will pitch up then. And other rights sales may help out, as will royalty payments if you get them, and PLR from the libraries. But I hope you can see why people say "Don't give up the day job" when you sign your first deal.