All humanoid NPC's with the exception of Mandalore and Hanharr (and Visas and Kreia who already are Jedi, of course) can be made Jedi.
The key is influence. Influence of 90% or above enables you to turn an NPC into a Jedi who shares your alignment, good or bad. Influence of 10% or below and they can still be made Jedi, but their alignment is opposite to yours.
How do you know how much influence you have? Compare their alignment to yours; when you are strongly light or dark - which you should be towards the end of your first planet, usually. For example, if you have light side mastery, a highly influenced character should be near to LSM. Or, alternatively, use one of the influence mods from
pcgamemods . Note that Kreia is an exception. Her alignment doesn't change noticeably with influence.
How do you get influence? Most potential Jedi have LS leanings. Doing LS things like helping people will get influence in most cases. Doing DS things will generally lose it, but: Atton (and Visas) can get influence from killing innocents if you defend your actions and claim it was for the best. Kreia can prevent influence loss if present, although it is easy to lose influence with her as a result. Most (except Bao-Dur) can gain significant influence if you are supportive of them in conversation.
All that remains are the trigger events (note that you need to be level 15 to make a Jedi):
Atton: You need to find the two Twileks in the refugee sector on Nar Shaddaa, who will give you an opening about Attons past. Speak to him about it. With enough influence - and three long bits of exposition - he will be a Jedi.
Bao-Dur: Keep talking to him whilst gaining influence. When he tells you about the influence you are having upon him, you are there.
Disciple (Female PC): Easy. After gaining influence he will admit that you do recognise him as he was at the enclave being trained with a view to becoming a Padawan. He will admit admiring you and hoping you could be his master. Can even be done without even leaving the enclave sub-level room where you find him...
Handmaiden (Male PC): Fight her three times (once after she joins the group, once after level 15, once after level 18). Ask her to put her clothes on and comment about her Jedi robes. Speak to Kreia about her mother. Speak to her about her mother. Tell her that you are worried about what happens to the Jedi teachings when you are gone. Result.
Mira: Talk to her about being restless (can only be done aboard the Ebon Hawk). This will lead to a discussion about Nar Shaddaa and you can tell her that Kreia showed you how to "hear" it. With sufficient influence, she will let you show her. Leave the Hawk with her in your party, and revisit the place (outside the entertainment module in the central area) and it will be job done.
This may sound incredibly n00bish but.......(spoilers) 
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