When you pick up your newly framed artwork, remember to handle it by the sides rather than the top of the frame. During transportation, works on paper should be kept upright or flat on their back, never sideways or upside down. If there is a large sheet of glass, guard against any possible twisting of the frame.
If you find you need to clean the glass, simply dust if possible. If a more thorough cleaning is necessary, use an ammonia-free cleaner, spraying a very small amount onto the cloth, not onto the glass, as the liquid can easily run down inside the frame, damaging the mat or the artwork.
The question of where exactly to hang the work, apart from being out of direct sunlight, is involved and subject to both personal taste and periodic shifts in fashion. Prior to the late 19th century, European collections were hung "salon style," that is, stacked closely together from floor to ceiling. In 1884, at the Grosvenor Gallery in London, James McNeill Whistler initiated the "gallery" style that is now used most often all over the western world. He contended that works of art need a certain amount of space around them, so he hung them much farther apart in a single line at a given height from the floor. In your own home or office you may want to use a combination of these methods, perhaps hanging most work at a standard height with generous spacing, but arranging small clusters of related paintings, or filling in spaces at awkward heights around fixtures or furniture. Be sure to leave adequate space, especially from inside corners.
The standard height in most modern galleries is 55 or 56 inches from the floor to the centre of the artwork, probably lower than you would tend to hang it without guidance. In a grouping the same height applies to the centre of the group. Finding the right height for the nail or picture hook requires a bit of measurement and arithmetic. A small sketch can be very helpful, especially in the case of double-hangs or groupings.
Very small works can be hung from a single hook, but larger ones are more secure and tend to stay level when hung from two nails or hooks at the same height and spaced about one third of the width of the picture apart. When hanging several works in a tight cluster it is much easier to ignore the hanging wire (which may not be at exactly the same height on each work) and hang directly from the D-rings or other hardware on the frame. In the case of very large or heavy works it is preferable to screw into the studs or use appropriately rated hollow wall anchors.
If you need help with hanging or consulting about the arrangement of the artwork, be sure to ask for an appointment when you pick it up.