Too many people just rush into an endeavour, whether it be a home project, a special meal or working out at the gym forgetting that preparation is a critical step in any undertaking.
The same holds true for your drywall project and with proper preparation the job will be much easier, and the end result will shine. Prior to drywalling, it is vital to make sure the walls are flat, and the framing is true which this is critically important for any successful drywall project. This is especially relevant for home renovation projects where, over time, studs or rafters may have developed a bow or cup which must be worked to make them flat. This can be accomplished with a hand-held planer for bowing, and with the use of shims for cupped framing.
To check your work, use a string or a laser to help determine how true your walls are before hanging any drywall. Another important framing consideration, prior to attaching drywall, is that all end joints need to be firmly supported which may require adding an extra stud, especially for inside corners.
Likewise, framing around windows and doors also requires a fastening surface for drywall in order to ensure good attachment. Always remember, good preparation will result in a superior result.