You could start from the chapter where the anime ended. Usually, there are forums or fan communities that discuss this and can give you specific chapter recommendations.
One option could be to check out popular online manga libraries such as KissManga or MangaFox. Just make sure to look for the official and authorized versions. Also, some bookstores might have physical copies or offer digital downloads if you prefer that.
Most BSD light novels often have complex characters. Since they are based on literary figures, they bring in the depth and complexity of those original personas. For example, a character might have the same traits as a famous writer but with a unique twist for the BSD universe.
The action and battles. For example, in 'Fullmetal Alchemist: Brotherhood', the alchemical battles are intense and exciting. And the unique settings. Take 'Sailor Moon', the magical girl setting in a modern - day city with other - worldly threats is very captivating. Moreover, the friendships and alliances formed during the adventures, like in 'Fairy Tail', add emotional depth to the story.