It can be frustrating to write a book. When I started writing I used to constantly compare myself to the big names and be annoyed I wasn’t writing at their level. Or the plot is just not going in the direction you had anticipated. Or your characters are so annoying and you can’t make them likable in your story, but you need them for the plot development.
First of all, don’t put yourself under so much pressure. You should compare yourself to the great names in your craft, but do it with the outlook to learn from them, understand their way of working and making it your own.
[DO NOT COPY other people’s work and slap your name on it. A copy of something is generally a shitty version of the original one and you deserve to show your own talent. And if you get caught you will forever be a fraud, and possibly have to pay huge indemnities, etc. Don’t do it, it’s not worth it.]
And if this is your first book, then make it the best it can be, but don’t be saddened that it’s not immediately a bestseller. Not only does it take time to sell books, but it also takes practice to be the best in the field.
Don’t pressure yourself to finish your project in a given time frame, especially if you’re self-publishing. Time frames are fluid and you cannot always ‘force’ the imagination out onto a page. To take a famous example, George R.R. Martin hasn’t finished the last two books for his ‘A Song of Fire and Ice’ series and has repeatedly missed deadlines. Try to have a schedule of when you’re working on your book, but don’t arbitrarily decide on June 16th it has to be finished, potentially releasing it with errors or a flimsy conclusion because you didn’t have time to finish it properly. Your name is on that work so make sure it’s the best version it can be.
This brings me to my last point; don’t set high expectations and then be disappointed and hate yourself when you don’t meet them. Don’t pretend you’ll write 20 hours a week when you can realistically only manage 5 hours. Then aim for 6 or 7 hours and be happy even if you only managed 5 hours. There is a difference between motivating yourself to sit down and do the work, and setting yourself up for failure by setting the bar way too high. And note that I said ‘way too high’. It’s healthy to set the bar a bit higher and encourage yourself to improve, but if you set it too high and you’re constantly disappointed you may give up on your craft altogether, which is also not the goal.