For your first character I suggest starting with a simple “class” like warrior (a knight, figther, something like that) instead of death knight and a vague character background instead of a fully detailed one
Make your character’s personality the main aspect instead of background information and history – f. ex. w/ Morsteth I ask myself how would this absolutely insane and evil man react to this every day situation and then role play it out
Of course a character’s history and the circumstances of the RP setting matter and the character itself can (and should) change over time but start simple
And join a guild (!) that has been around for some time to help you, the post below contains a long list of guilds that I know will help a new role player out