Over the years, I've built up an essential toolbox full of the things a writer needs. Like a good mechanic, I have a few select tools I use more than others and a few that sit idle for long periods of time but are indispensable when I need to reach for them. Your list of tools may be different, but here are the ones I find to be most useful.
The first tool any writer will pick up is something to write with. When I fist began writing I used a typewriter, now I use a keyboard. My primary writing instrument is an Acer netbook running Windows 7 Pro. This small PC is the ideal writing instrument because it's portable and relatively lightweight. I can easily carry it on a plane and it is comfortable to use almost anywhere. The battery life is decent and it runs all the other tools I use. The netbook however, would be incomplete without the programs I use to write - Scrivener and Microsoft Word.
I used Scrivener for the first time when I began working on Peacekeeper. I found it to be an indispensable platform on which to write. If you're a writer and you like to keep side notes, you must check out this wonderful program. The Mac version has more features than the Windows version I use. The program takes some getting used to but stick with it and you will not be disappointed. I also suggest getting yourself a copy of Scrivener for Dummies. I use Scrivener for the first draft and the second pass. After that, all editing is done in Microsoft Word.
Scrivener is not designed to produce final output although it can. For the final editing phases I use Microsoft Word. I compile the Scrivener manuscript into a Word document and then use Word's built in grammer-checker and spell-checker to do another quick pass. I print it out and give it to my wife for her to proof. This will take some time which gives me a break from the project. After my wife is done, I input her changes and then make a final pass. She approves any changes I make (using Word's track-changes feature) and then the project is done.
Another tool that is an absolute must for any writer is some sort of simple, set and forget, cloud storage. I use Dropbox for this. This wonderful, free, program keeps my manuscript synchronized between all my devices as well as keeping it safely backed up in the cloud without my ever having to think about it. It also hangs onto several past versions just in case I screw things up so bad I've got to start over. If my hard drive were to fail, my manuscript is safe and sound. If you don't have a cloud backup system in place STOP READING AND DO IT NOW!
If I'm ever at a loss for a word I fire up The Sage. This is a free (I use the paid for version) super thesaurus. I don't use it very often but when I need it, I need it badly. Give the free version a trial and if you're satisfied then please give the developers a little financial help and make a contribution. In return, you get the most up to date version of this wonderful product.
Don't forget the internet. It is perhaps the most powerful tool ever developed for writers. From the comfort of your home you can do complex research in a matter of hours that in the not too distant past would have taken a long trip, a healthy wad of cash, and more time than most of us have these days.
The final tool is education. This comes in the form of books, formal instruction, and feedback from your readers. Never stop learning! Broaden your horizons and experience the world by reading something you might never have considered reading. Be observant of the world around you -- you never know when a story idea will present itself.