Software Engineer job is a continuous race against technology if you are in development work.
First understand whether your software engineer job is “software development” job or “software maintenance” job.
If it is software maintenance job, you should not worry too much as there will be enough or more than enough spoon feeding training before you are on the job. On top of that there may be less work for the time you are spending except a few times in a year.
If complex maintenance tasks come on the way there will be an expert sitting somewhere fixing them if you are not able to crack quickly. So all in all you dont need to prepare for it.
Now the most important “software development” job. It is a constant and continuous race against time. Since you are fresher and it is your first job the major difference is
1. “There is no sysllabus for technology” so you need to continuously and constantly learn and practice new things in technology of your work.
2. You might have taken one full semester to read one full book that is prescribed for that semester subject. The major change that you need to understand is you may need to all these types of books on technology to be read in a week or in a month to deliver the job that you have on hand.
Your reading / learning speed must be changed to a faster level.
3. Sometimes you may not have a reference to check whether what you are trying to do to deliver a task is correct or not. So you should have the ability to decide whether it is good or bad without some reference point. This can only come by practicing the technology or similar tasks.
4. You need to get prepared to read about business and domains whether you like it or not. It is always good to be a techno commercial / techno business engineer than an Engineer only. If you do not try to get your hands wet in business domains you may have to work under a non technical person most of your career. So better jump into Business / Domain Knowledge.