Buy the best tools you can afford, a good trowel,secateurs, garden fork will pay for themselves over and over again. Look after them ,put them away when you have finished and they will last for years.
Paint the handles a bright colour like red or orange so you can find them again when you put them down while you have a cup of tea.
Those large brightly coloured plastic buckets are useful for lugging stuff about.
Try to get used to wearing gardening gloves, buy cheap and throw away is my motto.
might be a good idea to ask your GP when you last had a tetanus jab.
Don't be shy about asking friends for cuttings and seedlings, most gardeners are generous people who are happy to share advice and plants.
I love reading general gardening books written by people who know about gardening and who write well eg Christopher Lloyd, Beth Chatto, Marjory Fish, Vita Sackville West, they all have (or had sadly) gardens you can visit, which is another tip, go and visit as many other gardens as you can, the National Gardens Scheme is great, look it up online you will find lovely gardens near you, usually owned by lovely people offering home made cake and lots of ideas, it's a great way to spend a Sunday afternoon.