I am trying to do this currently. I've lost 7lbs since New years eve so far, just by making small changes.
My tips would be:
Start today, right now. Not tomorrow, or next week.
I bought one of those water bottles with the time printed on the side. It has helped me drink more water.
I've been doing work out videos for free on YouTube. I can't afford to join a gym, and I hate running. You can find work outs as short as 5 minutes. Yoga, pilates, dance, weights (I use tins of soup or beans from the cupboard), work outs specifically aimed at beginners, over 50s etc. Have a look.
I do the workouts first thing when I wake up, so that I can't put it off later. It's already done, and I don't have to worry about it for the rest of the day.
I've been drinking apple cider vinegar before meals. It's supposed to have numerous health benefits and help suppress appetite. I got a big bottle for a couple of quid in Morrisons, and I just stir a teaspoon of it into a big glass of water.
I know that I never stick to any strict diets, so I just limited myself to 2 treats a day. A treat could be a biscuit or a little mini chocolate. It's an improvement for me, because usually when I have a biscuit, I would have 6.
Just trying to eat healthier in general. More fruit and veggies etc, a little less bread and carbs. I still have them, but fill half the plate with salad or vegetables.
Hope this helps a little. Been working for me. You can do it!