Caring for your guitar is important. Controlling temperature and humidity are the main concerns. Always keep your guitar in its case when not in use. This will go some way towards protecting it from changes in humidity and temperature. Remember that a guitar is organic and still alive! It will move with changes in the weather.
Treat it as you would yourself, keeping it from extreme temperatures. Try not to allow the instrument to get warm to the touch. Wood gets increasingly pliable as the temperature rises above 30 degrees celsius or so. Leaving a guitar in a hot car is a recipe for disaster. Some of the glues used in construction will release with heat and the wood will warp and shift also. Also don't allow the instrument to get too cold - and especially don't allow it to get cold and then warm too quickly. This can cause cracking.
Guitars respond to changes in humidity. The wood breathes! In low humidity it exhales and the moisture content falls. This results in shrinkage of the wood. This is most noticeable on the top and back. When the top shrinks, the dome of the top, which is built in during construction, flattens. This causes the action to lower and you may notice buzzing on the frets when you play. In worse cases the wood will crack along the grain. This commonly happens in the UK during the winter months when the house is centrally heated. Although it is damp outdoors, indoors the humidity falls because centrally heated, double glazed houses are almost hermetically sealed. Try to keep the instruments in a 37% to 70% relative humidity (RH) range. You may need a humidifier to keep it above 40% in the winter. This is quite important - even more so than too high a humidity. I build my guitars in a controlled humidity environment which is kept at 42%-47% RH. Damage may occur to your guitar if the humidity falls below 35% RH. There are sound hole or case humidifiers and room humidifiers for use when the humidity is low. I would recommend using a hygrometer to monitor just how dry the atmosphere is where your guitar is kept.
During times of high humidity the wood inhales, takes on more moisture and expands. This results in a higher action than normal but generally speaking high humidity is less of a problem to the guitar, which can cope better with expansion than it can with shrinkage. If you keep the humidity less than 70% RH, you should have no problems. Also avoid rapid changes, which are more likely to cause cracks or damage the finish.
When I first set up an instrument, the action (string height off the frets) is quite low, and the neck quite straight. Within a few weeks or months the guitar 'breaks in' and depending upon the relative humidity and temperature, the action may rise up and make necessary a lowering of the saddle and sometimes a slight tightening of the truss rod (a very slight forward bow on the neck is optimum). This is totally normal. Remember it is an organic object. I offer a free, once only, service within the first 12 months to make any necessary changes after the settling in period (shipping at your expense).
My guitars have a lowish action as standard. Your personal needs for action can vary depending upon your playing style. I use D’Addario Phosphor Bronze light gauge strings on each new guitar.
The finish doesn't need much attention - just keep it reasonably clean. Use a 100% cotton cloth (old cotton T-shirt) to dust. I don't advise using polish. A slightly damp cloth is all that is required.
I give a lifetime Warranty to the original purchaser against faulty workmanship and materials which is not transferable. This does not include damage caused by extremes in humidity or temperature, improper handling or misuse, accident, and normal wear and tear. Alterations or modifications void the warranty.