Moreover, In addition, Besides, On the Contrary, However and Hence

by Eva

What kind of grammar structures must I use with the following words; moreover, in addition, besides, contrary, however, hence etc?

How often should I use them in sentences so my entire writing does not look so simple and dull?

How should I use them? I'm confused about their function; some of them have slightly different means too. Could you clarify this with some examples?

Where should I put them in my sentences? In the beginning, middle or the end?

"I'm going for a vacation next month; therefore I need your help to keep my mailbox safe." Does it sound more natural when I use therefore in this case?

Thank you so much for your helping, Ola, you're really great.