What is the best way to improve your English?

This summer I will be in Edinburgh for 2 months. I've thought try to relate to Scottish people as much as possible, look for some course or English's teacher and speak a lot. I don't know if this is enough to learn quickly and better.

What do you think?

What does 'guess which times were which' mean? In this context: Two of these times I was home alone, and two times I was out in the company of a lady: guess which times were which..

What does "and but" mean when are together? For example: My teapot was bought at Victoria Falls, and but the bag had been refilled with down in San Francisco. And what is "refilled with down" in Spanish? = rellenado con plumón?

What does " To be on relief duty" mean? To be on relief duty in a job perhaps is: estar de guardia o de retén?

First notebook entry: Introducing myself Hello everybody, I'm Maria, I'm 39 years old, I'm married and I have a little daughter. Now I live in Tarragona, one city of Catalonia, but I'm Castilian. My native language is Spanish and I speak Catalán too. I want to learn English once for all. I had studied English for a long time but I didn't get speak it and I could hardly learn it. These last 2 years I have learnt much more than all my life. However, it's not enough. I need to practice a lot of spoken English if I want to get a fluent English. I would like to be able communicate in English as well as I do in Castilian or Catalán.