A standard piece of vinyl siding measures 12 feet in length, making it rather unwieldy to hold in your hands for an extended period. Especially if you're working alone, set up two stepladders close to where you'll be working. Set out plenty of siding on the two ladders, enough to cover the area where you're working. For added convenience, set the strips at different heights of the ladder, so you can simply slide them straight out and against the wall at the appropriate height.
Instead of using stepladders, simply setting out two sawhorses allows you to keep a large amount of siding material in easy reach. As an added benefit, you can simply lift each individual piece up off the sawhorses. If you draw your siding off of ladders, by contrast, you'll have to set up the ladders so that you can pull each piece outward horizontally, from between the rungs.
The best means of holding up siding as you work isn't a thing but a person. So try to find a helper when installing siding. By working in pairs or even in a group of three, it's possible to hold the lengthy siding securely in place and check its orientation with a level before hanging it into position. An arrangement of ladders or sawhorses is far easier on your back than leaving your siding on the ground; however, without a partner, you'll still need to maneuver the siding onto the wall evenly.
Whether you use ladders, sawhorses or a couple assistants, set up your siding material at the back of your house to start the project. By starting at the back, you'll end up with the most seams facing the backyard and away from the front drive, giving your house the greatest possible curb appeal. In addition, as you fine-tune your technique, you'll reach the more visible areas of the home and produce the best-quality work there. Finally, strategies like setting out your siding at a manageable height reduce the amount of time you have to spend handling the stuff. Nonetheless, it's easy to get scratches or cuts from the sharp edges of siding as you handle it, so wear gloves to protect your hands.