Our guest Krista Nannery writes LondonDelicious.com, a blog mainly about restaurants in London, a city Krista lived in for six-and-a half-years before moving back to the U.S. in August. When she’s not eating, Krista’s traveling, and you’ll also find posts about her adventures abroad on her blog.

We caught up with Krista (via email) and asked her to help us plan the perfect trip to London.

1. Where-to-Go

What are some must-see sights for first-time visitors to London? Any off-the-beaten path local haunts that tourists should make a point to visit?
For your first trip to London, you MUST visit the Tower of London and go on a yeoman tour. The yeoman have so much character! Also of course check out the Changing of The Guard at Buckingham Palace. I’m a huge fan of the London Eye–the big enclosed ferris wheel across the river from Westminster and Big Ben and would highly recommend it. (Book tickets in advance to beat the lines.) Try to grab a boat from Tower Hill to the London Eye too. I’s a great way to see London.

I’d highly recommend having high tea while you’re in London. My favorite place is Brown’s Hotel in Mayfair, close to Green Park tube. I think they have the best food. One mistake that most tourists make about high tea is thinking that it will be a light snack. It’s NOT. It’s a HUGE meal. It’s normally all the sandwiches you can eat, all the scones you can eat, and all the sweets you can eat. So don’t do what my relatives normally do (even though I tell them not to) and have breakfast and lunch and make dinner reservations AND try to have high tea at 3 pm. It’s just not possible. You will slip into a food coma. Better to skip lunch and stay hungry for a bit and go to tea at 2 pm.

For off-the-beaten path, one of my favorite places in London is Brick Lane on a Sunday. The people watching is fantastic. All of London’s fashionistas come out to play. From Brick Lane, I like to wander up to Columbia Road Flower Market for some great photo opps. (But get there early to avoid the crowds. And this too only happens on Sundays.) I love listening to the true cockney accents, and a number of gorgeous little gardening shops have opened up down the strip. There’s also a cupcake shop and a few fashion and jewelry stores. Usually there’s some live music too.

2. What-to-Do

Are there any events or festivals in the city that are worth planning a trip around?
Open House London is really fun. It’s a weekend where a number of architecturally significant buildings that are normally closed to tourists open up to visitors. There are architecture tours all over the city during the weekend as well. This normally happens in September of each year and is a really interesting way to see London.

3. When-to-Fly

When is the best time to travel to London? (Times to avoid crowds? Times to save on hotels?)
The city definitely empties out in August, so that’s one option. If you’re looking to save money on hotels and flights, January might be something to consider. London rarely gets very cold and temperatures in January will usually be around 40 degrees. Personally, I really enjoy London in May and September. The weather is nice and it’s not as crowded as it is otherwise.

4. How-to-Shop

Any tips for saving money once you’ve made it to London?
Yes! Tons. Firstly, get an Oyster Card, which is what you’ll use to take The Tube. As soon as you get to Heathrow Airport, buy one and put 20 Pounds on it. As an example of the money you could save, if you were to pay cash for a single on the underground, it would cost you 4 Pounds. If you have an Oyster Card, it’s just 1.80 Pounds. And the most you’ll ever pay in one day using an Oyster Card is 7.20 Pounds. Related, definitely take the Picadilly line from Heathrow into London as opposed to a taxi. A taxi to central London can cost you 60 to 70 Pounds. If there are five of you, a taxi might be worth it, but otherwise, stick to The Tube. Another option is to take Heathrow Express to Paddington for 18 Pounds and then taking the tube or a taxi from there. (Heathrow Express is only 16.50 Pounds if you buy online.)

Second tip: don’t be afraid to take the bus. I find London bus stops to be wonderfully well-illustrated with maps and directions. Sometimes a bus can be the quickest way to get from A to B, so check out TFL.gov.uk (the London underground Web site) and plug in your starting and stopping points and review your transport options. It’s important to note that The Tube map is not geographically accurate, where bus routes normally are clearly marked! Oh, and a single on a London Bus with an Oyster card? Only 1.20 Pounds.

Thirdly, TopTable.co.uk is GREAT for restaurant deals. You’ll find all sorts of 50% offs and 2 for 1s. Always do a little research as there truly are great restaurants to be found in London. You just have to look for them a bit more!

Fourth tip: If you’re planning on going outside of London for a day or two (Bath or Oxford or Cambridge, for example), ALWAYS book your train tickets in advance. If you show up the day of, you can end up paying a ridiculous amount for a train ride that’s only 90 minutes or so. If the train tickets look too expensive, don’t forget to consider the bus service. (Check out NationalExpress.co.uk and MegaBus.co.uk.)

And last tip: There’s free wifi in abundance in London. Time Out London just did an article on where to find free wifi here.

You can find Krista on Twitter at @kristainlondon, even though she’s not in London anymore.