Yesterday, my sister gave us lots of gifts (things she bought in double and gave us one). I appreciated it and felt happy. We had a good time when I taught her some ways to learn English. I admire her for continuing to study English while she is a busy doctor. She also brings her son to my house more often. I feel happy with small things like that because normally we don't really get along with each other. Key Corrections "bought double" → "bought in double" (added "in" for clarity). "continuing studying" → "continuing to study" (correct verb form). "takes her son" → "brings her son" (more appropriate verb in this context). "get on with each other" → "get along with each other" (correct expression).

Yesterday, my sister gave us lots of gifts from things she bought in double to give us one of the two. I appreciated it and felt happy. We had a good time when I taught her some ways to learn English. I admire her for continuing studying English while she is busy working as doctor. She also takes her son to my house more often. I feel happy with small things like that because normally we don't really get on/along with each other.

Yesterday, my sister gave us many gifts, extras of things she had purchased in duplicate. I appreciated that and felt happy. We enjoyed ourselves as I showed her some ways to learn English. Her persistence with English in spite of being a busy doctor is something I admire. She also brings her son over often. I feel grateful for small things like that, because we don't always get along so well. It is ungrammatical to say "things she bought double" because "double" is an adjective. An adjective is not capable of modifying the verb "bought". Only an adverb can do that. You could fix the grammar by saying "things she bought doubly" but, although grammatical, we would not say it that way. So why is it permissible to say "things she bought in duplicate"? The reason is that a phrase like "in duplicate" is capable of doing almost anything. Not only can it act as an adverb. It can be an adjective or a noun, too. Phrases are flexible. "continuing studying" is not wrong but it is awkward to stick two participles together like this. You shouldn't use any at all, really. There is no need for them. What is the thing you admire? It ought to be a noun, so think of a good one (I used "persistence"). In "in spite of being a busy doctor", the participle "being" works well. Try to use participles in subordinate phrases like this. "More often" than what?