Suppose ,you have a list View in your activity where you have to download the data and corresponding images and show it in the list.
Generally if you download both the data and images once and after downloading of data you will show it in the list which will take a longer duration particularly depends on net connectivity speed.
For Reducing the time ,first we download the text ie.,names,links except images .we will put the download links in a stack and we will download them after displaying the list-view by using late downloading of images.
First the list will show and images will show in their corresponding position in the list whenever it got downloaded exactly like android market application.
This will reduce the time and we can download as many items we want to show as like working of android market list view.
You can download the sample working project by clicking here Download the full working Project.
Hope it helps you in writing fast applications.
If it doesn't work for you ,please let me know.