Begonia tubers . the best way to grow ?

i usually follow the instructions and if the plants dont do well I take them back as being of poor quality.
usually you place the tuber round end down in compost so 1/2 the tuber is covered. this leaves the dished side uppermost. they are watered sparingly almost allowing the compost to dry out each time. they need to be kept frost free but with good light. when leaves are growing well increase the watering and once in flower feed 2 weekly and deadhead flowers constantly to keep them 'on their floral toes'. when flowering is over and plants have died back keep them in a frost free place without water until next year and start again. hopefully thats what your instructions say.