Everyone's phone is different. You may have a Motorola Droid with just a three-home-screen vanilla version of Android, or you may have an HTC phone with seven screens, a ton of extra widgets and other UI enhancements. Regardless of your situation, though, there are a number of things you can do to keep your home screen organized, so you can spend less time flipping through them and more time using your phone.
Try a New Home Screen Launcher
One of the first and best things you can do is get a different home screen launcher. The default is fine, but there are a few options out there that provide a ton of useful options that can help you customize your screen based on your workflow.
My personal favorite is LauncherPro, available for free in the market (though there is a $2.99 version that comes with some good-looking widgets) and set it as your default launcher by checking the "use default for this action" when you first hit your home button. It's clean-looking, remarkably fast, and comes with a nice scrollable dock at the bottom where you can put your really commonly used apps. I also find this useful for "toggle" switches, like toggling Google Voice on and off, or visiting previously mentioned Smartbar's Quick Settings window (more on that later).
After installing LauncherPro, you can access a number of new, home screen-related settings by going to the home screen, hitting the menu button on your phone, and tapping Preferences. You'll have to just poke around; many of them are performance and appearance-based, giving the dock new looks or icons, but there is one in particular that everyone should take a look at.
The second option down is Homescreen Settings, where you can choose the number of screens you have. You can choose a number from one to seven, and also pick which one of those is your default screen (you'll want it to be the one in the middle, probably—i.e., if you have seven screens, you'll want the default to be screen number four).
How Many Home Screens Should I Have?
It seems like there are two general philosophies on organizing one's home screen: some people like to have as many screens as possible, with a ton of apps, shortcuts, and widgets filling them up. Others like to have just a few screens with the most important apps easily accessible, and the others close by in folders or other app launchers. Here are some strategies you can use for each method, starting with those of you who like a lot of screens.
Using a Lot of Home Screens
Find your overview shortcuts: Using a lot of home screens gives you all kinds of options for organizing things, but it can also result in a lot of swiping. Luckily you don't need to constantly swipe through them all just to get to an app or a shortcut. If you are using LauncherPro, you'll notice that tapping the home button once while already on a home screen will give you an overview of all your screens. You can then tap on one of them to go straight there. This makes having seven screens less of a time-wasting burden. Note that other launchers may have this ability, too, though sometimes they're located in different places—often long-pressing the app drawer icon or pressing the dots next to it that correspond to your home screens will get you a similar overview.
Categorize by screen: Now, this may seem obvious to some, but one of the best tips I can give you for using all those screens is to organize them by category. I, for instance, have my default screen which has some of my more used apps like Gmail, Google Talk and Facebook, but my others are either organized by music, productivity, games, social networking, etc. For example, my music page has a large Music widget for changing tracks, as well as shortcuts to the Last.fm, Pandora, and apps. It makes it easier to know where you have to go to access a given app.
Don't underestimate the power of widgets: If your phone can handle the slight performance hit they sometimes incur (I've found that LauncherPro is still blazingly fast on my Motorola Droid with seven home screens and lots of big widgets), they're really convenient. You can view lots of information from a given app without even opening it up. For example, to see my to-do list, I can just swipe one screen to the left; I don't even need to open my to-do app. Similarly, I can read Facebook and Twitter without waiting for the apps to load just by scrolling through the widgets. It's a nice time saver when you just want to take a quick peek and don't need to do any serious work with the app in question.
To add a widget, just long press on any empty space on your home screen and pick "Widget" from the menu. You'll get a list of all the widgets available to you and you can select one to put it on the home screen. You can also drag them where you like just by long pressing on the widget, just like you would an app shortcut.
Using Fewer Home Screens
If you prefer just a few home screens, you obviously want your most important and most used apps at the ready, so put those on the home screen first and foremost. If you have any leftover room, you can either throw a widget or two on the screen, or you can add folders, which save you the trouble of scrolling through your app drawer when you need a slightly less common app. Organize these folders just like you would home screens by category: throw your music apps in one folder, productivity apps in another, and so on.
To add a folder, just long press an empty space on the home screen and choose "Folders" from the menu. You have a few presets to choose from, but if you just want a custom folder with a few shortcuts in it, pick the top option. Then just drag your apps on top of the folder's icon, just as you would on a computer. To rename the folder, open it up and long press on its title bar.
For quick access to other apps, there is a convenient feature in Android where if you long press the Home button on your phone, it will give you a list of recently used apps. This can be pretty handy for fast app switching, especially if you don't have a lot of shortcuts right on your home screen. You can also organize your apps using labels instead of folders (sound familiar, Gmail users?) using an app called Apps Organizer, available in the Market.
Shortcuts, Shortcuts, Shortcuts
App shortcuts are always useful, but the neat thing about Android is that there are a ton of other kinds of shortcuts you can add to a home screen. You can add a shortcut to one of your browser's bookmarks (so you can have quick access to, say, Google Reader, or your favorite technology blog), shortcuts for navigating to a specific address (so you can always get back home with the touch of a button), or specific contacts (so you can call certain friends with two taps instead of scrolling through your contact list every time). These are huge time savers, and after adding them to your home screen you'll wonder how you ever lived without them.
To add a shortcut, just long press on an empty home screen space and choose "Shortcuts" from the menu. Depending on the apps installed on your phone, you'll have a number of choices, so look through the list and see which ones would benefit you and your workflow the most.
Apps That Make Life Easier
There are a lot of other apps out there that can enhance this experience, but there are a few that have made my life particularly easy. One is previously mentioned Power Strip, which gives you access to widgets, apps, and other shortcuts without you even having to leave the screen you're on. It's quite useful for toggling on certain functions, or changing your music track without leaving your working application. The other is previously mentioned SmartBar. This app has a ton of features (if you love task killers, this app will make your life a lot easier), but my personal favorite is the Quick Settings feature that is, essentially, a more advanced version of the Power Control widget. You can toggle on and off things like Wi-Fi, GPS, home screen rotation, and even your unlock pattern. It's pretty handy to have around, and doesn't take up any space on your home screen if you don't want it to (unlike other apps, you can put it in your menu bar if you prefer—I like it in LauncherPro's dock).