1- Using a productivity tool

If you haven’t use CodeRush or Resharper, you should start now. They give you a lot of useful short key, advanced auto completions, better refactors, templates… Check out CodeRush screen cast, you will definitely be impressed.

Which’s one is better, CodeRush or Resharper? There’re lot, lot of articles, blog posts about which one’s better on the internet. I think they’re both really good and it’s more about which one you feel more comfortable with.
For more information:
ReSharper vs. CodeRush: Part 1 « Ian’s Blog
Scott Hanselman’s Computer Zen – ReSharper vs. CodeRush
ReSharper 4.0 vs CodeRush/Refactor! — Smack Down results

2- Using an ORM tool

using Subsonic or NHibernate could save you a lot of time. They could access to your database, analyze and generate all ORM classes in just minute.
More information:
Subsonic Homepage
NHibernate
Getting Started with NHibernate – Techniques
Introduction to SubSonic
Config Subsonic for winform

3- Reusable code

Writing something reusable could take longer then writing some code which is work for a specific situation, however with reusable code, you could just use them again. If you need to copy and paste some code in your project, it would help if you could make them into a functions. Easier to reuse and maintain…
Store some handy code snippets so you could access them easily. I made a category in my website to store all the useful code so I could find them easier.
Code Vaults

GotCodeSnippets.Net
Code Snippets in VS.NET 2005

4- Multi-line text (or inline SQL)

It’s a small but really helpful tip. I see a lot of query string write in this format:

"SELECT *" +
"FROM tblProducts" +
"WHERE productID = 1"

There is a much better to write such a query.

@"SELECT *
FROM tblProducts
WHERE productID = 1"

It’s much easier edit or copy and paste.

5- Comment and group code

I think I don’t need to write much about comments. You could spend a few minutes(or even only seconds) to write some comments which could save you hours in the future.
Using #Region to group part of codes so you know which part of code doing what. Close the regions also help you scan the code much easier.

6- Test unit

Using a test unit such as NUnit or MbUnit could save you a lot of time. If you haven’t known about Unit Test yet, there are a lot of useful articles about them:
Unit testing – Wikipedia, the free encyclopedia
Unit Test – C2
nUnit Homepage
mbUnit Hompage

7. SVN (Subversion control)

Subversion is a revision control, manage the changes to documents, programs… It’s mostly use when you work as a team when the team maybe changing the same files. However you could use that even when it’s just one man project. Always safe to keep a history of what you did and you could undo later if you get into problems. It’s also a way to stop comment out code as you could always revert the code back with subversion control.

If you use subversion in your company, you should make your own SVN server for faster transfer and more security. If it’s just a personal project, using an free SVN host could be enough.

Git is another(maybe more powerful then SVN) option. You could learn more about Git here: The guide to Git for absolutely beginer

SVN client/information
Subversion
VisualSVN
Google project hosting
Github

8. Get the latest news with RSS

Technology changes every day, and we developers should always have our hand on the latest, coolest technology. The best way to stay up-to-date is subscribe to the top websites in our field using RSS (For more about it) . Now you have the latest news not every day but every hours, every minutes.
Some websites you should subscribe as a developer:
My website. HieuUK
DZone
DotNetKicks
Become a Better Web Developer Using RSS

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• Config for Subsonic in Winform
• Did you know about db4o – a brilliant object oriented database
• Delete query using Subsonic
• How to make plugin $.extLinks: Control the links
• The guide to basic Git for absolutely beginer