A lot could be said here from a lifetime of learning, depending on what you are maintaining. Here are some general guidelines over a broad parameter.     1) If you can see your footprints in the lawn after you have walked across it, it needs watering.   2) Don't wait for fungus or insects to wipe your lawn out. Diagnose properly and make the appropriate treatments. It's always cheaper to maintain than replace.     3) Pre-emergents for your lawn and flower beds will not work if you miss the timing window to applicate.  Feb/March spring application, Oct/Nov fall application.   4) Post-emergent weed control should not be done when temperatures are over 90 degrees.   5) Plant growth regulators should be applied before spring green up to have full effect.   6) Crepe Myrtle trees should not be topped. This does not promote bloom growth. Limb up only to ten o'clock and two o'clock and remove suckers from base. Fertilize early spring and late fall with high phosphorus fertilizer. 7) It is best to do any severe pruning after 3 rd frost of the year but preferably late Feb./early March so it does not look barbaric as long before new foliage emerges. 8) Drip irrigation conserves water better than spray heads or roter nozzles. 9) Do not run irrigation mid day as wind drift will effect the spray pattern and lesson the available desired water to target plants or turf. 10) Install a water present control switch on your irrigation system to prevent watering while its raining and to conserve resources.(How many times have you seen a sprinkler system watering while its pouring rain? This wastes money and natural resources.) 11) Special attention should be given to any main entrance areas as this is the "most seen"area of the property and deserves special attention.Don't skimp on time and creativeness here! 12) Install a lawn and landscape that will not only love its new home but will thrive with out high maintenance requirements. 13) Everyone loves blooming flowers....Why have haven't you planted any? 14) Always add soil conditioners and vermiculites to new shrubs and tree holes.They will grow faster,be healthier,require less of your time to maintain and be around for the next generation too enjoy! 15)  Use professional quality products and equipment for professional quality results.  Do not skimp here.   16) Lawn and bed edging looks the best with natural bordering. (Sorry, the plastic bed edging and porcelain garden gnomes have to go).   17) Pattened plants that look fantastic are worth more because "they do more". Example: Encore Azaleas bloom spring and fall, Knock Out Roses are better performers because the need for fungicides and insecticides have been bred out of the roses, etc.   18) When installing a new lawn, whether it be sod or seed, do not skimp on prepping the finish grade and machine rolling for a putting green like smoothness (your Fanny will thank you later when you are on the riding lawnmower).   19) Creating bed lines that have proportionate contour not only looks better by breaking up right angles, but also eliminates string trimming with a weed eater which saves you time and or money.   20) Remember the story of the old gardener who worked day and night learning design techniques, planting scheme layouts, what plants and turf worked best and why for years. One day a traveler was admiring his work and said "I would give my life to be able to make a garden as beautiful as you." Hence, the gardener replied, "But good sir, I did." When in doubt..."HIRE A PROFESSIONAL!"