Once you have a timeline and you have created a basic outline to begin your writing process. It is a good idea to look for themes that can be carried through specific parts of your subject’s life. The themes can bring the stories to life. Additionally you can watch the character development this way.
It would be a good idea before you begin writing to decide which events you are going to include and the ones that you are not going to include. This will make writing much easier, because once you are in the flow of writing, you will not have to stop to make these type of decisions.
Then you need to begin writing. If you are quoting directly from the subject’s point of view, make sure that is clear. You can italicize or put in quotes the stories. It is also nice to do a mix of straight narration on your part where you explain things such as where he lived, went to school, and other basics. Then mix in the stories that stand out in memory. You can also mix in the third party sources if you have them. Stories from brothers and sisters would go well with the childhood section and so on. This will make the narrative much more interesting to read.
When you have finished writing you should begin by doing a quick edit for grammar and spelling mistakes. If your subject is still alive, you should then have him read over the material and see if you would like any changes made to the history. If he is not alive you may consider having his wife or children do the same thing. They may have things to add or want you to check dates.
Once you have done this you can choose your method to share this others. It may be in a larger book on several members. You may choose to post it on a website. If you do this, you may want to wait until the person passes away out of respect. If the person is alive you will have to get permission before you publish it. If you have a video to go with the story, you may want to give that to family as well.