Yes, they speak English in LA so that's one thing you don't have to worry about.  But if you don't know the 411 (that's American for info) of the big city, you could be in trouble. Here are some tips to make your stay as smooth as possible: 

• Stay in Santa Monica or Venice Beach. They are on the beach and both are big Brit ex pat spots. If you'd like a more central location, stay in either West LA, West Hollywood, Beverly Hills, Hollywood, Studio City. 
• Hire a car. LA is a car city. You will need one. You can turn right on a red light as long as the route is clear. Remember to park in the same direction as the traffic. Don't expect people to indicate when they change lanes, or to change lanes from either the right or left lane. 
• If you don't have a good international rate on your home mobile, buy a pay as you go cell phone (it's cell phones not mobiles!)
• Remember LA is 8 hours behind London. 
• Valet parking is everywhere. Don't worry they won't steal your car!
• Remember sales tax is added on to the price tag at check out. Currently CA sales tax is 9.25%.
• Tipping. 15-20% is standard. This is expected when eating out. In Bars, usually a $1-$2 a drink order is acceptable, same with valets. 
• Allow for traffic. When you organize meetings, just remember that rush hour in LA is usually from 3.30pm-7.30pm. 
• Check www.sigalert.com for traffic conditions. 
• Use google maps or mapquest for traffic directions.
• Jay walking (crossing the road at a non designated point) is illegal and you could get a nasty on the spot fine.
• LA is not a late night city. There are late bars but few and far between.
• Restaurants close at 10 p.m. There are lots of great restaurants from the super cheap to very expensive. Shopping malls also all have food courts with good cheap food. 
• Get your internet sorted so you're in touch with everyone over email. A laptop with wireless is essential. Starbucks have free wireless. 
• Set up an online phone service with Skype. You can then set up and make calls from your laptop using wireless internet. You can also set up an answerphone on that line.
• Foreign exchange. You won't find many exchange booths in LA, so the easiest way is to get cash is from an ATM so don't forget your cards or pin numbers. 
• Network with everyone you meet. Go to parties, bars, dinner, coffee shops, AA meetings and sell, sell, sell! This business is all about who you know. 
• Check out the movie theaters. American audiences are much more enthusiastic and don't fear airing their opinions in a theater. Almost entertaining as the film itself. 
• Do the LA thing while you're here. Rollerblading and people watching at Venice Beach, Universal Studios, Disneyland. 
• Take photos of yourself at the studios and the Hollywood sign. You can use this as great PR back in the UK should you have to make another low budget Brit film.