If the desired landing spot is being undershot and a shallower approach is needed, both power and pitch attitude should be increased to readjust the descent angle. It is important to remember that a constant airspeed must be maintained. The pitch and power change must be made both smoothly and simultaneously. This will result in a shallowing of the glidepath with the resultant aiming point moving towards the desired touchdown point.
Want to learn more about approaches and landings? You can find the Airplane Flying Handbook here. If that link does not work, copy and paste the following link into your browser. http://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/airplane_handbook/
Runway incursions are the leading safety threat to aircraft on the ground and those approaching to land. Do your part to minimize this risk by preprogramming the radio and navigation equipment before you taxi. If you are given an amended clearance that requires you to reprogram the equipment, wait to enter the new information until you are stopped in the run-up area or ask Ground Control if you can stop for a moment along your taxi route.
Keeping your mind focused on the task of taxiing and adhering to ATC instructions is your first and only priority at this point. Keep yourself and your passengers safe - do your part to avoid causing an incursion.
More information about the dangers of airport surface deviations and mitigation strategies available can be found at the FAA Office of Runway Safety web site at http://www.faa.gov/airports/runway_safety/.