One of the most important features of written academic English is the correct use of linking words. Take this sentence as an example:
In contrast to the difficulties researchers faced in collecting the data, the analysis phase of the research project was straightforward.
The use of the linking phrase in contrast effectively joins the two ideas. This means that when you are writing you have to think of the relationship between your ideas. These relationships are often categorised into functions such as:
the idea being that you think of the relationship between the ideas you want to link and then join choose an appropriate linking word which performs that function.
I find it really hard to teach linking words in an interesting way! It’s almost impossible to explain which ones you can and can’t use. The fact is you have to look at lots and lots of examples of linking words being used properly. Here’s a good page from Birmingham City University on linking words with examples and good exercises too. I have linked here before and will probably do so again one day! It’s here.