Hi, I've been lurking on this sub for a while and have just made an account. I'm in the UK, so there might not be as many things available as the US - but I do find Swagbucks to be the best rewards site.
I always run all of the 6 apps for mobile, that's 60 swagbucks per day, and occasionally they will pay me a couple of extra swagbucks as a bonus. Having said that, they recently seemed to have updated one of those apps - Sportly.tv, which no longer runs on my phone - it just gets stuck on a loading symbol. Have tried uninstalling and so on, but it's still the same.
I do the games daily for 10 SB per day (that's 70 SB per week)
Sometimes I will get an "Instant Survey" on the homepage - which I think is around midnight for Swagbucks time, but they're always really quick and very rarely get disqualified. Only yesterday I got one - it paid me 387 SB! I was gobsmacked.
Last month I purchased a new laptop in order to run Swagbucks videos on, as my old one couldn't cope with them. So I was basically running the vids on the watch section and installed the Swag Button with the toolbar TV. I accidentally spilled a cup of tea on my keyboard and now it doesn't work :(
I can't even see a way to get the cover off so I can clean it. Currently I'm saving up to get it fixed, but I would recommend a good laptop that can cope with all the vids -- with no liquids in the vicinity! I'd only been using it a week :(
I don't do offers very often at all because I find when I complete them just the way they want (even if it's free) that they rarely credit.
Have you tried tasks that come through CrowdFlower? Swagbucks is the only rewards site that I know of where you can still use email to sign in -- you don't have to have a Facebook account. There's quick and easy tasks available there -- and sometimes they have their own surveys, which are usually quick and easy, with no chance of getting disqualified. I always find that a good boost to the daily goal if there's nothing else available.
Other than that, I'd say Ncrave which you do already, are my favourite way to earn, but sadly it seems to broken for the UK at the moment.