You just go, whether you have motivation or not, you have to make yourself go because to be honest, if you wait for the motivation to kick in, you'll probably be waiting a long time! That's what I had to do with the gym the first time I joined. I didn't really feel like it but I knew I had to and so even though I didn't really want to, I just got on and did it. This time I feel much better about it and enjoy it more but I still have days where I don't want to exercise, like we all do, but you just have to keep on, whether you want to or not. That's the hard bit though!
Personally, I don't do cheat meals and I don't really see the point. You're either doing something or you're not and if you're going to do it, go all out for it. That doesn't mean you won't have over days, we all do sometimes but I prefer to keep them for occasions like because I'm going out for dinner with friends or it's a birthday, wedding etc. rather than a weekly thing. I think, personally, that if you're having a naughty take away then what you're doing all week will be pointless. You could lose a couple of lbs in the week but then put all of that back on because of the takeaway and spend the next week trying to lose the gain and maybe 1lb more or something, to then put it on again with a takeaway. It's an endless cycle if you're doing that every week. The problem with takeaways generally is that they're high carbs, high sodium and high fat so you'll see a big gain from them. It won't all be fat, mostly water weight, but can still be hard to shift. So keep it as a treat, not a cheat, and have it less often.
As for what the poster above me said. Those skinny friends can't do all of that because they go to the gym or run, though that'll help, it's because they'll have high metabolisms. Some people are just like that but unfortunately, the people who are going to be on a site like this aren't. Diet and exercise play a huge part in trying to lose weight, just seems a shame to work so hard all week to set yourself back every week with a takeaway. Not saying don't ever do it just, like I said before, keep it as a treat.