When packing for a trip to London it might be hard to know what you really need and what will remain in the suitcase unused. All of this advice comes from personal experience from times when I wish I'd remembered something, or wished I hadn't brought something.
Write down all the non-800 numbers for credit cards, and other places you may need to call while away from home, as these don't always work from overseas. You can either find the non-800 numbers printed on the back of the card or call the 800 numbers before you leave to get the overseas number.
Copies of Itinerary
Always put a copy of your travel itinerary inside your each piece of your luggage. This can really help if you get separated on the route. Every year, thousands of bags never make it back to their owners as there is no identification inside.
Copies of Passport
Always put a copy of your passport inside each piece of your luggage. Again, this helps with identification if you get separated from your bags, but it also helps if you lose your passport while on vacation as it is easier to get a new passport issued if you have the details of the one lost.
You can also store copies of important documents online with a photo uploaded a scan to a photo-sharing site such as Flickr and set the privacy levels so only you can see it.
Destination Contact Details
Make sure you have the telephone number and address of your destination in your hand luggage AND your checked-in bags. Have the number written in the way you would need to call from all stages of your trip. For example, you may change planes in another country but not actually leave the airport. But if you've been delayed you may want to call your final destination to let them know. One time, just after I had checked in my bags, an announcement was made that the airport was closing due to bad weather and there would be no more flights. And, you guessed it, the telephone number of where I was staying within my hold luggage.
Think About the Weather
Consider the season and weather at your destination. It can be hard to remember what to pack if it's cold where you are but warm where you're going. Find out more about London Weather and see the monthly Events and Weather Guides for advice on what to wear.
Now we have to pack liquids in our hold luggage, why risk shampoo all over your clothes when you could buy some lovely toiletries at your destination? Rather than a hindrance, I see this as a chance to try something new. And in case you are worried about wastage, I can assure you it's easy to buy travel miniatures in London too. Boots and Superdrug are High Street chemists which mean you will find branches everywhere in London, including the airports.
Limit the amount of jewelry you wear on board or, better still, leave it all off. It will save the time at security checks before boarding when you have to remove it all for the metal detector and it will be safer in your bag. Pack your jewelry in a roll and store in your carry-on bag. Never place valuables in your hold baggage. And if you can't bear to lose something then it's probably best not to take it.
Streamline your keys. Do you really need to take the shed key, garage key, the neighbor's back door key, brother's house key, etc. if all are in your house and you have that key? Also, do you need the 10 'cute' key rings? One is probably enough when traveling. And never pack your keys in your hold baggage, just in case you get separated.
Roll, Don't Fold
To avoid crumpled clothes when you unpack always roll your clothes instead of folding. And roll items together, not individually.
Find out more from the About.com Europe for Visitors Guide:
Pack Your Suitcase to Thwart Wrinkled Clothes
Ensure you don't pack prohibited items in your hand luggage or hold baggage. Innocent looking items such as household cutlery are not allowed on board.
Find out more from the BAA Heathrow website: Packing Tips.