The reflexive pronoun is used when the object and the subject of the sentence are one and the same: - Ghazal pours a tea for herself. - He wants more time for himself. - That poor guy finally did something nice for himself. - You go right ahead and make yourself at home. (Note: "Make yourself at home" is a common expression spoken by a host to a guest, inviting them to relax and take their coat off, have a seat, etc. - Come in. I have to put a few things away in the kitchen; but please, go on into the living room and make yourself at home.) The reflexive pronoun can also be used for emphasis: I myself baked this cake. (No one helped me do it.) Ned closed the shop himself last night. (Usually he has am employee do it.) I hope this helps. Please ask me if anything is still unclear. :)

Depending on your tense your first sentence could read: I poured a cup of tea for myself. I am going to pour a cup of tea for myself. I want to spend more time by myself. I hope that helps. :)