AureliaRiddle, a player from The Elder Scrolls V: Skyrimshe became famous for being herself recreated in game practically perfect.
In addition, after making his model, he also re-made his father in the game, just to make his family more present.
AureliaRiddle and her father in Skyrim
How long do you think it took him to make it? About two hours per model. Not very much, considering the final result. To succeed he used mods that add sliders to the editor and more detailed heads. He also installed others to improve the quality of textures and eyes, to make the characters look more realistic.
For similar results, AureliaRiddle recommends shooting at least two photo of themselves, one in front and one in profile and use them as references, perhaps after printing them. Alternatively you can use a mirror, but with photos it’s easier.
In the photos try to appear as natural and relaxed as possible. Finally, remember that you will only use half of the face, because the other half will simply be mirrored. Game editors only allow you to create symmetrical faces.