We have all done it.
Set an amazing book down, grabbed our heads and started wailing. "I will NEVER be as good of a writer as he or she is!"
Maybe you aren't as dramatic about it as I am, but still. We have all experienced writer envy at some point or another. Maybe you wish you could write storylines like so-and-so. Or plots. Or descriptions. Or had the readership of another author.
What do we do with these feelings of inadequacy?
Focus on your strengths. Stop harping on yourself. No, you may not be able to write like whoever you are currently reading but you can write exactly like YOU and that's something that no one else can do. Figure out what you do well and focus on making that even better than before.
Find out what makes them good. Reread one of your favorite books by one of your favorite authors. What do they do well? What do you admire most about their work? Figure out how they made you, as the reader, feel like that. What wording did they pick? What tone did they set?
Aim higher. Learn everything you can about writing. Dissect every piece of good writing you find. And practice. Keep practicing as much as you can. You will see improvements in your work! But stay true to you and your style.
At the end of the day, keep in mind that just like every other talent out there, we all have our strengths and weaknesses. Andrea Boccelli and Britney Spears are both singers but goodness knows they are different and have their own audiences, songs they sing well and songs they don't. It's the same with writing.
Is there a writer you want to be more like? What do you do with writer envy?