What opportunities can you take in each year of university? Assuming a four-year degree structure:
First year
Not much is open to first years. If you're keen to intern in the summer, cold emailing is probably your best bet, although there are a few official programmes that aren't picky about the intern's age. Else, start to figure out what kind of industries and sectors you're interested in. Attend a few talks and events.
If you're interested in consulting at all, BCG has an insight programme held in September of your second year at university; apply for this in January of first year. Otherwise, get involved in societies. Figure out what you're interested in.
If you're interested in investment banking or consulting, apply to every spring week you can in the summer of your first year. It's a numbers game.
Second year
Hopefully you'll have a leadership position in a society by now. Start networking: speak to alumni and people you know about their career journey and think about what might suit you.
Your spring week will be in April, and if you interview well at the end of it, you may secure a summer internship for the summer of your third year. Otherwise, start applying to penultimate-year internships in the summer of your second year.
You should have a strong CV by this stage, checked over by lots of people, and hopefully you'll have at least 1–2 work experiences on there. A lot of firms hire directly out of their intern pool, so put in the work now and you won't have to apply for graduate roles in the summer of your third year (which are even more competitive).
Third year summer
Hopefully your summer internship gets you a graduate offer, but if not, start applying to graduate roles in the summer of your third year (yes, during your internship).
If you're keen on investment banking graduate roles, it's advisable to apply for off-cycle internships and convert these to grad job offers rather than applying for graduate roles directly, since there are so few places.
Fourth year
Have a good one.
If you're on a three-year degree
If you are on a three-year programme, push everything one year back.
This timeline is particularly catered towards banking, which has the earliest recruitment season. For most other industries, push application dates forward by 3 months.
The CV review scores your CV against what banks and consultancies screen for, whichever year you're in.