If you want to make a good house, some basic rules to follow.
1. Use dark wood. Light wood almost always looks bad, especially if you use lots of it. Ideally you want beams and supports to be dark and if you can panelling to be light, which means majority dark wood, minority light wood.
2. Avoid the bright stones and boughs.
3. With stone mansions, you need to use a fairly even distribution of stones to get variety, 125 of one and only 50 of several others will result in only the major stone being used.
4. Variety of materials/colours is nice, but don't go overboard, 2 types of material is usually enough, maybe 3 if the 3rd is only used for minor details (like a door).
5. Make sure your materials match. Don't go using white and red stones, shit looks dumb.
Follow these basic tips and one day you too can have a house that looks this good
http://i.imgur.com/50jE2Fn.jpg