Paper backed veneers can leave a line that contrasts with the wood, at the corners. Some suppliers have a product called NBL (No Black Line) Veneer but it's expensive and only comes in full sheets. Veneer with no backing will tend to be less obvious but it can be fragile. There are ways to make it more flexible, like glycerine, and they don't affect glue-up.
Some woodworking stores have demonstrations and veneering is sometimes offered. They usually have veneering tools and veneer, often in multiple piece packs. If you go to the link, maybe you're close to one of the cities that The WoodWorking Show will be going to and they always have a booth selling packs of veneer, usually for a good price.
Link:
http://cms.thewoodworkingshows.com/cms/
As with any other technique, it takes some education and practice to become good at it.
