1) Stick an extra lane on most motorways, dual almost all A roads, and widen inner city roads.
It was half term last week, and every day my mainly motorway commute was halved, saving me an hour a day. It would pay back in terms of reduced stress and pollution, and increased productivity.
2) Make public transport work. I'd love to be able to get on a bus or train and be able to get a bit of work done, lounge about etc.
3) Ban unpaid work for businesses. Internships only serve to ensure that people without cash are unable to get work experience, and that people with cash, do.
4) Sort out education. Don't care if it's grammar schools, free schools, or whatever, but the current system is very poor. See point 3. Class is the major determining factor for educational attainment in the UK.
5) Gas anyone who can't watch football without making a series of semi orgasmic noises.