Turn on your 3G network. If your iPhone is currently not set to access 3G, it relies on the slower Edge signal for data transfers, which can slow Internet operations. Tap your "Settings" icon on your main menu. Select "General" and "Network." Tap the switch beside the words "Enable 3G" so that the word "On" appears.
Access a nearby Wi-Fi network. Although it does not affect your signal for phone calls, a good Wi-Fi network can give you must faster data transfers for Web-related activities. Tap your "Settings" icon, followed by "Wi-Fi," and select your local network from the list. If a password is required, a popup window will prompt you to enter it.
Step outdoors. If you have a weak signal while indoors or underground (such as inside a subway terminal), Apple recommends that you step outdoors in order to place yourself more clearly within the signal range.
Purchase a third-party signal booster. They come in two basic varieties: those that you attach directly to your device and those that you can place inside your home (like a modem or router) to improve the cellular range in the immediate area.
Restart your iPhone. For unexplained signal lapses, you can sometimes restore your strength with a simple reboot. Hold down the "Sleep/Wake" button at the top of your iPhone until the "Slide to Power Off" message appears. Move the slider across the screen. Hold down the "Sleep/Wake" button again to turn on the iPhone.