A lot of authors believe that the first book is really a tough one to write. Yes, there are indeed a lot of difficulties with this one, but I have to say, in most cases, this first one is tough because you are trying to find your own voice, you are trying to understand the market and, more importantly, trying to find a way to move your writing from a hobby format to a professional writing format.
When an author sells that first book, he or she is often under the direct guidance of a great editor (which I have to say ALL of my authors have been blessed with) and potentially an agent. This team is spending a great deal of time working with you and molding you. They know this is your first book and they want to make sure your intoduction to your public is going to be fantastic. In simple terms, you cannot launch yourself into public with a flop.
For authors, this is really that honeymoon phase of their career. The excitement of that first cover, seeing those revisions, working with PR people and so forth.
But then comes your second book...
Assuming your first book does relatively well in it's debut, you will likely find yourself with a group of readers who have now found the next best thing. They want more of your books. They will start creating expectations for your writing. Yes, many of these expectations may be unrealistic, but to them, they think the world of you. Now, as a writer you have to live up to that first book and hopefully do it better.
It is that second book that you will find yourself trying to fix all of the mistakes you found yourself doing with the first book. You will strive to create even stronger characters, more complex plots and so forth. The difficulty comes from the fact that we forget that writing DOES TAKE TIME. 1 published book will not suddenly make you an instant genius when it comes to your writing. For this reason, you cannot put that burden on your own shoulders.
Do you want the next book to be better? Sure. One of the things that creates an immediate career failure for writers is when we see the same thing being produced over and over again without seeing anything new.
There is also a second struggle and that is the fact that the editors and agents, although they are 100% behind you, the expectation is that you have learned a few of the things they taught you during the first round of edits. They simply do not want to have to re-explain things to you that you should have figured out already. No, they are not expecting 100% perfect, but they want to see you make some strides.
Don't worry though. This is a learning process. You will get there. Just keep plugging away at this and don't be pressured by unfair and unreasonable expectations.
Scott