Make sure you tell your parents, in person (or on the phone if you're not nearby) before you change your relationship status or post a picture of the ring on Facebook. They really should be the first people to find out. It's worth calling other close friends and relations as well - in the age of social media phone calls are getting rarer so it will be extra-special for those who receive a call.
Take care of the ring
If your ring doesn't fit perfectly get it re-sized as soon as possible. You don't want to lose it in the first few days of your engagement!
You should also get it insured: add it to your home insurance and check that it's covered outside of the house.
Set a date (ish)
OK, you don't have to pinpoint the exact day of the wedding but people will ask when you're planning to get married. If you can pin down a month and year or even a season it will answer the question and give you a focus for your planning.
Prepare the planning
Weddings take a lot of planning and organisation. Even if you're thinking of hiring a planner you'll need your own way to keep track of things. Get yourself a large notebook and a ring binder to be used only for wedding-related stuff - it will make the planning a whole lot easier.
Sort the budget
Every wedding needs a budget - set yours now. Work out how much you can afford to spend and how much you need to save each month to achieve this; it's worth setting up a dedicated wedding bank account to help you stay on track. If parents are offering to contribute find out how much they want to give and add it to your total.
Make a guest list
This doesn't have to be exact at the moment but you will need a rough idea of numbers before you go ahead and book anything. The number of guests you have will impact how far your budget will stretch as catering is the biggest single spend in a wedding. And you can't go venue-hunting until you know how much space you need for everyone.
Get wedding insurance
I can't say this enough. The cost of wedding insurance is tiny compared to any wedding budget and it's usually valid for 2 years from when you take out the policy. EandL and John Lewis offer good cover and are inexpensive. Please, just do it.
After you've done all the above...that's when the fun stuff starts. Finding ideas and inspiration for your wedding. That's right, your wedding. Nobody else's. You get to do it your way. Buy magazines, read blogs, develop a serious Pinterest habit and most importantly....