Based, in part, on my discussions with a respected and prolific South African author.
It is best not to be too conscious about the process. Don’t cripple yourself. Don’t break your own mirror.
The writing of books is like a journey and, sometimes, you reach the end.
Go with the flow. Let it come from the unconscious.
Don’t get diverted by interesting facts or ideas that are only indirectly related to the task at hand. Don’t waste time.
Historical novels leave room for details, for example the way servants might kneel at the hearth in 18th century Dutch South Africa would be reasonable for an historical novel. Such portraits from daily life add to the texture of a fiction or a description of the past. They do not necessarily fit into a standard historical narrative. On the other hand, a ‘standard’ historical narrative need not be embellished.
Be mindful of mistakes when reading languages that are not your first language. You will avoid embarrassment and (possibly severe) criticism. You will earn the respect of those proficient in those languages.
Get feedback from other writers, friends, acquaintances, the man in the street.
For historical novels, familiarize yourself with the historical setting. Visit museums, historical places, look at books on costumes etc. Speak to experts on the field.
Write with a pen or pencil or fountain pen. Write on paper. Computers tend to give writing a cut-and-paste effect.