It's only ever as difficult as YOU yourself make it.
Try to stick to it. Make it a challenge! Don't have any carbs, stick to veggies and protein - stay away from butter sauces, or tomato sauces (they often have lots of sugar and oil added in!) - opt for 'grilled' options. Try to ask for salad dressings 'on the side'.
There are a lot of hidden ingredients in even the most seemingly innocent things...
If you feel like you want to have a drink - try not to make in an everyday thing - one day stick to some Diet Coke (though not technically allowed on Lite!) - and as for alcohol - stick to mixers. A shot of (25ml) vodka/gin/southern comfort etc is about 55 calories. Coupled with a low-calorie mixer like Diet Coke/Slimline Tonic/Sugar Free Lemonade will be about 60 calories per drink - so you can keep an eye on it that way. Plus these technically speaking will not break ketosis. What happens is when we ingest alcohol like this - the fat burning process gets put 'on hold' as the liver processes the 'poison' that is alcohol instead of the fat.
Beer and wine aren't quite the same unfortunately, so I would stay away from them - they are much higher calorie wise and have carbs/sugars.
Go into your holiday with a healthy mindset - however, remember if one day you have something 'outside the diet plan' - don't let it spiral into 'oh well, I've blown it now, might as well have everything else'. Eliminate the damage before it gets too great! The power is in your hands.