There are so many different things you can do i think the first thing to do is go and get a book for some ideas.

Also buy a good general book (the cheap ones are rarely good) on how to do gardening like the RHS Encyclopaedia of Gardening, and, as you flick through it, try to distinguish between things that sound like hard work you don't want to do, and things that sound like more what you want to do.

Find out what the bushes and trees that are already in your garden, and remember that it can take many years to get a plant to maturity, and moving well-established plants is often not possible, so consider carefully before you rip them out. Even if it is something you currently think you hate, a bit of pruning and maintenance might turn it into a very useful and attractive shrub. Nevertheless, there were quite a lot of plants in the neglected garden I took over that I nevertheless decided to remove, including quite a few of the trees.

One thing in gardening is "improving the ground". I have horribly stony soil - if I sift the soil about 25%-30% of it is pebbles. Easy-grow hard-to-kill plants will grow despite it. However to make a vegetable patch, and to plant things that prefer soil to pebbles, I have had to sift tons of pebbles out of the garden, and do much repeated addition of compost to the soil to improve it. This is very hard work. If you are lucky you have nice soil already, but if you don't then bear in mind that growing just what you want and making it look like the Chelsea Flower Show, and/or for food cultivation, will require a lot of work in soil improvement.