It is a pain in the bum frankly but totally doable, and much better today than in the past. Great advice up there, so, instead of more of the same here's some advice on stuff.
Genius Bread and Yes You Can bread are great- Genius seeded if you want a white-ish, Yes You Can or Genius for brown. Nobody does a really good white loaf IMO. Genius rolls, accept no substitute. Warburtons rolls are useless, they fall apart, but the bread's good if you want real-bread texture and handling and don't care that it tastes of NOTHING. Cooking bread basically.
Dove's Farm pasta is ace, needs very little special handling, most gf pastas are decent these days but they tend to be a bit slimy, which means washing them off with boiling water.
Tesco and Asda often have a freezer GF section, which is ace. Asda do good GF pizzas too (Dietary Specials I think) Ironically the only problem is they're a bit stingy on the toppings!
Tesco probably have the best GF selection- their own brand biscuits and cakes are mostly high quality, they do a very passable if rather heavy naan bread, they sell warburton's excellent fruit loaf and muffins, and their cherry bakewells are ace (though could use more filling!) Marks and Spencers do a brilliant chocolate cake but it's often hard to find.
Oats... Oats is a tricky subject, because for years they were verboten but these days pure oats- that is oats prepared in a wheat free enviroment- are often considered safe. But still avenin intolerance is considered allied to gluten intolerance.
Flour... Glutafin do a range called Select, which aren't 100% Gluten Free but have a sufficiently tiny amount of wheat that they're considered coeliac-safe. Codex Glutanicus is not what this is actually called but I can't help but think of it like this. Anyway, it is fantastic- the "multi purpose" makes the best dough by miles, the best bread, the best cakes... Can be had on prescription too.
Eating out- find places you enjoy and trust, make sure they know it. Wok and Wine in Edinburgh have my custom forever. Thai and indian food should be pretty safe, but it's worth having a word. Italian, well, lots of italian restaurants will cook with gf ingredients but it doesn't necessarily mean a good outcome to be quite honest. No wonder, GF stuff isn't exactly hard to cook with but it's different, so they need experience with it to get good results.
Above all don't be afraid to ask!