An article I read today in 'Outdoor Photographer' (one of the best Photo mags) had a single line that is a good candidate for the 'Golden Rule' of photography. I cant remember the exact wording but it went something like 'you are not photographing objects, you are capturing light'. By planting this firmly in your mind you will learn one of the most important differences between a snap and a picture. Most ancient monuments are great subjects for photography and the best advice you can get is to let the monuments look after themselves, the photographers job is to make sure the other ingredients of a good photo are there and shown to their best advantage in the resulting picture.
When I started taking photographs as a hobby first I assumed going to spectacular places and photographing spectacular objects/animals/events would make spectacular photographs. This is really only the starting point, once a photographer gets to a spectacular subject and decide what angle or view will show it to its best advantage he/she puts the subject to the back of the mind for a while and concentrates on the other even more essential ingredients, the quality of light, reducing the complexity of the background or selecting a background that better complements the subject and the mood which comes from the weather.
Quality of light possibly has the greatest input into the feel of the photograph. Going back to the 'Golden Rule' idea, what you are really capturing is the light reflected off your subject, a photographers greatest concern is the quality of that light. The low, warm sun in the hours after sunrise or before sunset is ideal and the lower contrast makes for great colour photos. During the harsh mid-day sun it is much harder to capture mood in colour but in B&W the strong contrast picks out the shapes and textures which can be ideal for infra-red or straight B&W.
One of the greatest differences between a holiday snapper and a landscape/portrait photographer is the huge importance the photographer places on background. As mentioned earlier, the subject is usually worthy enough of a photograph so the photographer instead concentrates on the background, this can make the subtle but crucial difference between the snap and the 'work of art'. Leaving the subject to look after itself, scan the rest of the scene in the viewfinder, are there distractions that can be removed by moving a foot or two? Is the subject isolated against a pleasing background or hidden in the clutter? 'Keep it simple' is the golden rule and always strive to reduce the complexity of the scene. This can be done in lots of ways, by isolating the subject against the sky or by blurring the background with a small aperture in camera or blurring in Photoshop later etc. etc. Not all ancient monuments have beautiful backdrops, for the rest it pays to spend some time thinking about things in the corner of your eye.
The weather usually controls the mood of the photograph, clear blue skies make nice postcards but are usually devoid of any mood. Approaching bad weather and low, billowing cloud add plenty of mood and the very brief moments when the sun breaks through brings untold joy to the patient and usually soaking photographer! In emergency cases the sun can be substituted with a crafty dab of flash.
Once these basics have been considered, then you can worry about composition. For me anyway, mood is far more important. I dont over analyse about composition though from studying art as a kid I think I just go along with what feels right without resorting to charts on leading lines, zig-zags and repeating patterns. These are useful though a 'normal' landscape photographer can wander for as long as they want until the elements of good composition fall into place around them, we are stuck with the surroundings chosen thousands of years ago when hedges and houses were few and far between and todays countryside can be just plain bland at times.
With that said, a little thought on a few starting pointers improves things dramatically.
Rule No.1 in composition is never place the subject in the dead centre. while normally true there are exceptions when the subject looks particularly good or nothing else in the frame justifies placing it anywhere else.
Rule No.2 is never divide the frame in two with the horizon, one worth considering for every photo but there are occasions where it cannot or should not be avoided and its best to go with what feels right.
Rule No. 3 is divide the frame into three columns and three rows and place important elements either along the lines or at intersections. This is the famous 'rule of thirds' and while over-used it is still extremely effective without you appearing a 'clever dick'.
Not really a rule but valuable nonetheless is the addition of foreground interest. Keep an eye out for an interesting rock, colourful clump of flowers or aging tree to give your photos an extra dimension on top of subject and background. This can be critical with wide angle lenses, but again you sometimes just have to make the most of what elements are in front of you.