The first thing read, is the last thing written.
Every teacher loves to read a paper that begins with a strong, healthy introduction, one that has a hook, and narrows to a sound thesis, one that intrigues you, makes you want to read more because it gives you a roadmap of what to expect, one that discusses the gaps the paper will seek to fill. We teach our students these things, and we reiterate them in the Writing Center. One of the most important things we can tell them is when to write the introduction: How about last?
This is not to say that if they need to begin at the beginning, we are taught all things linear growing up, that they shouldn’t. I tell my students to go ahead, get it out, get the ball rolling, BUT don’t forget about it just because you made it through and got to the “good stuff.” I remind them that the introduction is the first impression the paper makes, and sets the tone for the rest. I also remind them that it, including the thesis, can change as the paper evolves. I ask them to compare the conclusion and the introduction, to consider how pertinent, connected, focused what is being said in each is to the body. I tell them to wait until they are finished with the bulk of the paper, when they are “in the zone,” when they “own it,” and then revise the introduction.
I also find that often there is a “nugget” that is great in the conclusion, but it far greater if moved to the introduction, perhaps even as the hook (I did that with my opening line of this post.)
Here’s some terrific information on Introductions from UNC: