What people enjoy about eating out will vary wildly so there is only so much useful information I can offer on this subject besides what I know based on my own experiences and preferences.

1. The food in England isn’t as bad as people say it is. That is a trite, outdated idea. You know how everyone says American food is terrible, “plastic”, artificial, blah blah blah, but you know that’s only because they’re going to Ruby Tuesday’s, TGIF or somehow thinking McDonald’s represents an entire nation? It’s the same here. Go to an establishment that sells crappy food, and you will have the impression that English food is crappy! But that’s a generalisation and it’s not true. There are TONS of places selling fresh, organic food. No “white sauce”! There are pubs that serve up terrible jacket potatoes (baked potatoes), dry steaks and soggy lasagne, but there are plenty others that focus on fine pub food, with local roasted meats and vegetables.
2. There are, of course, great curry houses (Indian food) in London. They are not all the same, but sometimes it’s kind of a close call. We’ve lived in three different boroughs of London and found a favourite curry house in each one. Try your local curry house first and branch out from there until you find one you really enjoy. if you’re lucky, you will find a nice one nearby or that delivers.
3. There are good chain restaurants, and bad chain restaurants. In the food-snob-Mecca that is the Bay Area, chain restaurants get no love, ever, even if they might deserve some. In London, there are decent chains and they aren’t derided simply for existing in several areas around town. I won’t bother rating these however I do have some reliable stand-bys. These are all casual chains: Strada (for risotto), Zizzi (for spicy pasta and some people like the pizza here), La Tasca (the food here is just ok, but they do sangria–the real draw!), Gourmet Burger Kitchen (again, I don’t rave about this place but it scratches the itch), Nando’s (the service at all Nando’s can be hit or miss. But the chicken and chips (fries) are fab). Apparently there is a Chipotle here now but I haven’t tried it. Go to Benito’s Hat if you have a burrito craving. Benito’s Hat is the closest I’ve found to Northern California burritos. As with all “Mexican” food in the UK, it’s not quite it, but sometimes it will just have to do.
4. With the causal chains, check for vouchers online. Places like Zizzi and Strada often have some kind of offer for Sundays through Thursdays.
5. Nicer restaurants in London are also reliable in terms of good food and service. I don’t frequent nicer places on a regular basis as most social activity here is based around the “pub then grub” concept. One tip is to check TopTable.co.uk for reservations, reviews or offers (it’s similar to OpenTable). If my husband and I are going out for an occasion, I’ll check TopTable for reviews first.

Tipping

1. Tipping here is typically 10%, maybe 15% if you are very happy with your service. (None of that atrocious 20%+ business like San Francisco. Jeebus.)
2. Do always check the bill to see if service is included, as it surprising is, whether you are a single diner or small group.
3. Never tip for drinks at a bar or pub, even if you feel like it would be a nice gesture. It’s not really viewed that way. I have a friend who pulls pints in the evenings at Shepherd’s Bush Empire, a music venue. When they have an American act performing, it draws an American audience and the bar staff knows this means they are probably going to get a few tips that night. Meaning they don’t expect tips at any other time. Don’t feel bad; you are not expected to subsidize anyone’s wages.
4. Don’t worry to much about tipping too little, especially if service is lackluster or basic. You will soon become accustomed to a lower salary that is taxed more than what you are used to, and those single pound coins jangling in your pocket will be like gold to you.