If that is your manifest:
<manifest xmlns:android="schemas.android.com/apk/res/android";
package="com.faizanchaki.firstappproject" android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="8"
android:targetSdkVersion="17" />
<application android:allowBackup="true"
android:icon="@drawable/ic_launcher" android:label="@string/app_name"
android:theme="@style/AppTheme" >
<!-- no activities declared here -->
</application>
</manifest>
Then you are missing the declaration of a main activity like:
<activity android:name=".MainActivity"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
you should declare the main activity in your Manifest so that your app icon will appear in the android launcher and you will be able to actually start your app. Just put your Activity name and add it to the main manifest where I put the comment.