To get the most out of an open day, it pays to have read the prospectus (well at least the bits about the courses you are interested in). If you've got a map of the layout of the university, work out where you want to go and if you can walk round. Be alert to the possibility that you are only visiting one campus of a multi-campus university or college. It is important to know whether you will have to mount a major expedition between lectures.
Open days come in a number of varieties and it's worth knowing the differences between them since you will get different things out of each kind.
First, there is the publicly advertised mega-event, usually held in July, August or September. These happen infrequently and the general idea is to turn the place into an equivalent of EuroDisney. All the best lecturers give their pet talk, the science and engineering labs mount displays explaining their research, jazz bands play outside the Vice-Chancellor's office, balloons abound and a good day out is had by all.
As you will have gathered, these events are good if you want to get an idea of how the institution is laid out and the location of departments and key facilities such as the students' union bar. They are also great opportunities to discover what the institution thinks are its highest- profile subjects and people. However, they are not so good if you want to chat to students about their experience or to members of the academic staff about things such as course choices, entrance requirements or career opportunities for their graduates.
If that is what you want, look out for schools and colleges open days. These may only be advertised to local schools and colleges, have less emphasis on the jazz and balloons and more opportunities to get specific information from admissions officers and current students. It is also likely that representatives of the student welfare service and students' union will be available. They are good sources of information and advice about things like the facilities for disabled students and the ins and outs of student finances. The students' union also runs all the hundreds of clubs that you will be able to join and you can check whether there are students who share your interests or alternatively how easy it would be to start a club of your own. The sports facilities are also likely to be on show; a good opportunity to check out if they have what you need and whether there is likely to be a lot of competition to use it. There are national university championships in many sports and it could be worth knowing how well teams you might be interested in have performed. It's also worth checking whether it would to cost anything to use facilities and whether your expenses would be covered for away fixtures.
Next there are open days held in the spring and autumn as part of the application process; these may be held by a particular department and designed to give applicants a chance to find out more only about it. Or they may include opportunities to have a guided tour of some or all of the rest of the university or college. Usually the invite to attend this kind of open day is only made to candidates who have already received an offer and sometimes there will be a special programme arranged for parents who are acting as taxi drivers. Most of these days do not involve a formal interview, but it can be very useful to have someone's undivided attention for 15 minutes if you have detailed questions. So don't hesitate to ask for such an opportunity.
You are likely to get lots of invitations to UCAS open days, particularly if you have applied for a subject where there is low demand for places. It is worth going to as many as you can, although it's all time out from classes during a crunch period.
Finally there are open days that are interview days in disguise. You will arrive to find that part of the programme is an opportunity to impress one or members of the academic staff. Remember, be positive, and have a few questions of your own handy.
Also bear in mind that in many cases they are just as keen to impress you as you are to impress them. So watch out for sales talk and don't hesitate to ask penetrating questions. You may find that academic staff are not too clear about things like accommodation costs and the price of a plate of chips in the refectory, so save those questions for students.