Good cocktails rely on the quality of their ingredients and the authenticity of the recipe. Try researching classic cocktail recipes and experiment. Old cocktail books from the 1850s to 1900s will provide guidance on classic recipes and ingredients.
Choose spirits carefully, trusting the iconic, recognised brands. Sugar syrup is also a vital ingredient; always use one made from cane sugar.
There is also some essential equipment that every home bar should have: traditional Manhattan three-piece shaker, Boston shaker, Hawthorne strainer, fine strainer (like a tea strainer), zester, muddler and hand held fruit squeezer.