A couple of tips for exercise is to focus on building muscle rather than cardio- though cardio seems to yield more results short term increasing muscle mass increases your BMR and AMR and means long term you'll be able to eat more calories to maintain your goal weight. I used to do HIIT (high intensity interval training) fairly religiously but got a bit lazy and I definitely would say it had more of an impact than focusing solely on cardio. To work out a strength training plan that suits you you should probably research home HIIT exercises to construct a plan for yourself but this seems like a pretty good start if you want to get going right away- http://www.burnfat-buildmuscle.net/fat-burning-hiit-home-workout-routines/
. Also don't be scared if you put on a couple of pounds after starting a new routine- it's water weight from your body storing glycogen to rebuild your muscle, as your body gets used to the exercise it'll go away.
I won't preach too much about diet 'cause as you said yourself you don't want to go on a 'diet' per say, just want to warn you not to eat under your BMR, if you don't know what that is there are a few websites that'll calculate it for you, a lot of people go on VLCD for speedy weight loss but it's not worth it in the long run, your BMR is the bare minimum your body needs to function normally and if you don't give it at least that not only will you feel the effects physically during the diet (dizziness, queasiness, irritability) but you'll be at a much higher risk of plateauing or even regaining it all when you're done.
Anyway, good luck and I wish you every success losing weight