Why would anyone hate you? Why would you be feel like you will be disgusting?
FWIW you don’t have to flirt to become romantic with a partner. You can just be straightforward and say how you feel. “I like you. You’re really pretty, and you make me happy when we talk.” Some people won’t like that level of honesty and transparency, but it sounds like you wouldn’t want a partner who wants flirting.
Don’t be gross or vulgar. Don’t treat anyone like a sexual object, and take rejection well. It can be crushing to work up the nerve to tell someone how you feel, only to be turned away, but that’s part and parcel with consensual relationships. There are many fish in the sea, and if you hyper-focus on just one, you’re setting yourself up for failure.
Once you’re involved in a relationship, you can try out a little more flirting. Wink or make suggestive comments. Quick kisses on the neck or a pinch might be acceptable depending on the context. Don’t do anything that makes you uncomfortable, and don’t do anything that makes them uncomfortable. Part of a relationship is discovering the boundaries of another individual. You’re going to cross a few lines, and it is important to react with understanding and respect. If your partner reacts negatively, apologize and adjust your behavior. This can be tough, because the boundaries may change with context (e.g. flirting at a bar on a date vs flirting at a family function) or over time (young relationships are more exciting) but as long as you demonstrate that you care about your partner, you can take some calculated risks.