Writing is an art, a craft. Much like painting a masterpiece, one must consider the whole picture when writing a novel. This applies to shorter works, as well, but especially a novel, I'd say. I've oft said anyone can write a decent if not good novel, and I stand by that statement. Not many do it, because it is hard, but anyone can do it, because it is easy. Ponder this paradox, if you will, but here are ten tips I have for aspiring authors, now that I have traveled down the road a ways (though not far enough). Some of these tips may not be for everyone; some may wish to do the complete opposite. It is up to every individual writer to determine their writing process. At any rate, here's some of what I've learned.
1. Always write when you feel like it.
As the logline suggests, always write when you feel like it. It's when you burn with the most passion and when you long to write the most that your work will shine the most. It will, of course, require some rewriting/editing, but with adrenalin and passion as fuel, you will turn page after page.
2. When you don't feel like writing, do it anyway.
Even if you don't feel like writing, it is a good idea to do so; writing should be routine. I've sort of fallen out of my routine, which leads to procrastination and no work done. If you have to wait until you feel like writing, then you may never finish anything. Not a good idea. Writing a novel is a time-consuming task, so it is not feasible to merely work when you feel like it, even though that may be the best time to write.
3. Place grammar aside.
A good writer will likely have a good sense of grammar, without actively thinking about it. But any mistakes can be corrected at a later time, and if a mistake persists, it's not the end of the world, nor your book. A book is about a good story, not good grammar. Unless it's a grammar book, of course. If bad grammar and misspellings are EVERYWHERE, it can be very annoying, but one minor mistake somewhere is not the end of the world.
4. Write where you feel comfortable and happy.
This does not necessarily pertain to a real, physical location. Your state of mind should be one in which you can work. If you long to be someplace else, you may not be caught up in your work. Perhaps you check Facebook every other second, and Twitter the second you're not on Facebook. Not good.
This can also be about a real location, of course. I've noticed that I feel better and can more easily work when I've recently cleaned. When my place is messy, it's not as easy to work. Same thing with the lighting. I've noticed I like to have a faint, warm, orange glow—a cozy light. I don't want my writing environment to be too bright or too dark. But I suppose this is about personal preference.
Just one really good tip: Turn off your access to the Internet. I don't do it; I don't have the willpower. But it is surely a good idea.
5. Never make promises too early.
I've done this. I was too optimistic with when I'd be able to release my book. You have to keep pushing back the release, or you must release the book when it's not ready. Either way, it's not a good idea. The editing process will take longer than planned, especially if you have beta readers. It's better to wait until you feel ready or if you know you will be ready soon, and then schedule the release. Make promises only when you know you can fulfill them.
6. If you feel lonely, turn on the TV
This is something I like to do. If you sit alone and write on your computer, you may feel a bit lonely or detached. Or you may find company in your characters, if you are ill—mentally ill. What I like to do is turn on a casual television show, so I can have it on in the background. It should preferably be a show you've seen a few times, so it doesn't distract you. And if you are too easily distracted, then this tip is altogether bad. I usually have on Friends, Seinfeld, The Simpsons, or something similar. This works as a white noise that can make the writing experience easier. Music might also work, or perhaps you enjoy silence. Find your own perfect environment in which to write.
7. Make sure all information is in order.
Before you start to write your book or series (especially series), make sure all your background information ("lore" if you write fantasy) is in order, especially for your characters. It is okay to invent new bits of information along the way and fill in gaps whilst you write, but get a consistent feel for your world. And document it well. No matter how much time you spend working on your books and worlds, you'll not remember every detail, so having documents in which you keep this information for easy access is something I highly recommend.
Personally, I'd gotten a feel for my epic fantasy world (The Long Lost Tales of the Dragonlands), but I've not yet fully documented everything. If you have a basic feel for the world and know how you want it, then you needn't be finished before you start to write, but I still recommend it. One thing I can also note is that while you write down information about your characters and such, you will have more ideas and this will flesh out your world and the people living in it.
The worst mistake a writer of fantasy and science fiction can make is to obviously contradict established facts. So get your facts straight.
8. Plan your novel.
I would suggest doing this, but it is up to every writer to decide if and to what degree they plan out their novels. Still, it is a good idea to know where you want the story to go. You mustn't have all events clearly planned out, and improvising can lead the story to interesting places you never could've thought of while planning, but a basic skeleton can still be useful and can make it easier to plan out big emotional scenes based on character backgrounds and story.
I've noticed, even though I plan out my novels to a degree, I improvise exactly what happens in the chapters and I also come up with new ideas along the way. It rarely ends up exactly as I'd planned. The skeleton is simply an easy way to get to know the creature that is your book.
9. Writer's block?
No such thing. Well, there is, but whatever roadblock is in your way, you can drive through it. Yes, sometimes you may get stuck, but try to push forward. What you write at these times may not be the best, but this can be fixed later. You must get past the rough patches so you can get to where your writing truly shines. Once the novel is finished, rewrite/edit, rewrite/edit, rewrite/edit.
10. Have fun!
Always remember this: You don't write for your readers, but for yourself. We write because we love it, don't we? To have fun is necessary for turning out a good book. If you hated writing the book, if you didn't have fun, there is a risk the work will reflect this. Pour your soul into the book. Think of only yourself. Then think of the readers. The best tip I can give any writer? Have fun!