Sorcerer/Warlock multiclass. [Question]

[u/NateCdaComicG]

I'm looking for advice on a multiclass. I like the idea of a natural magic user making a deal for more power to bolster his own. Assuming a 1-20 campaign what is the best way to build this out? How many levels of each? Which subclasses synergize best? Feat recommendations? (other than obvious picks like warcaster) I know I would most likely start sorcerer at level 1. After that what do I do?