1. Show; don't tell.
When you are writing make sure that you are not just spouting description or telling your reader how your character is thinking, feeling, etc. Use sensory and showing description to allow your readers to get inside your character and feel as if they truly know him and understand him. It is kind of like the difference between talking at someone and talkingwith them.
2. Get more into your character's mindset so that the reader can connect with him/her.
This usually involves making use of showing instead of telling, but also to devoting time to your character instead of your plot (although this time with your character will of course be integral to your plot in many ways). Make sure that you are making your character a person, rather than simply a character, that is three-dimensional and relatable in some way.
3. Make the focus of the story tighter and eliminate unnecessary plot lines.
As you write, be sure that you always keep in mind what the main focus of your story is and try to keep the narrative going in that direction. What is your story about? Who is important? Don't give in to the desire to share every single possible thing that occurs - hone the story so that is it moves at a fast pace and engaging.
4. Be critical with edits - don't just think as a writer but as a editor with commercial elements in mind.
When editing your story, put your business hat on. If a piece of writing is incredibly gorgeous but is unnecessary to the plot and drags the story down, cut it! Keep in mind what is critical to keep your audience turning the page and be sure to think of what makes your story commercially successful and viable. Those elements will be important just as important for attracting agents and editors as the beauty of the writing.
5. Careful of overdoing description or plot - don't stray into fandom.
It is easy to get caught up in your story and your characters, but be careful that you don't let yourself get carried away! Like the idea of keeping the focus of your story tight, don't fall so in love with your quirky, funny character that you turn him into a caricature rather than a real person. Similarly, don't let yourself get carried away with overdone descriptions that the reader will skim over to get to the action.
6. Create tension and emotion.
Again, this all ties into the idea of not overdoing description, having a strong focus, and showing instead of telling. Your reader will not be captivated if there is nothing that constantly propels the plot forward, whether that be friction between characters, a heated romance, or a scary situation. Make sure your writing is active, i.e. has plenty of dialogue to counterbalance descriptive moments, as well.
7. Know your genre.
This is so important. For instance, if you are writing a middle grade novel, make sure you know the difference between middle grade and YA.
Well, that's my advice for the week! If you have any questions about what I've written about (or if I've done a horrible job explaining something), let me know in the comments section!