You don't need much. Here is what actually matters, what doesn't, and why.

Most home bars fail before the first drink is poured because the owner bought the wrong things. A twenty-piece tool set in a bamboo stand looks impressive, but you will use four items and the rest will rust. The truth is that a small collection of the right tools will make better drinks than a kitchen drawer full of gadgets. Here is what you actually need.
These four items let you make ninety percent of classic cocktails.
First, a Boston shaker — two metal tins that seal together. It is faster, colder, and easier to clean than a three-piece Cobbler shaker, whose built-in strainer inevitably clogs and leaks.
Second, a Japanese-style jigger with internal markings. The dual-sided design (typically 6 cl and 3 cl) gives you speed and accuracy.
Third, a Hawthorne strainer — the coil-spring type that fits snugly over the shaker tin.
Fourth, a long bar spoon, at least 30 cm, with a weighted end and a tight spiral. It stirs, it measures, it layers, and it retrieves olives from jars.
Buy these four first. Everything else is secondary.

A wooden muddler with a flat base is essential for Mojitos and Old Fashioneds. Avoid muddlers with teeth — they shred mint and overwork sugar. A hand-press citrus juicer, the hinged lever kind, is non-negotiable. You cannot squeeze enough lime juice by hand for a party, and bottled juice is flat and metallic. A Y-peeler produces the clean citrus twists that garnish a Negroni or an Old Fashioned with precision. Finally, a fine mesh strainer, small enough to hold in one hand, allows you to double-strain shaken drinks — removing ice shards and herb fragments so the texture is silky rather than slushy.
Ice is an ingredient, not an afterthought. You need two capabilities: large cubes and standard cubes. Large silicone molds that produce 5 cm cubes are ideal for rocks glasses — they melt slowly and look serious. For shaking, standard freezer ice works, but you need plenty of it; a half-empty tray produces warm, watery drinks. Crushed ice can be made by wrapping cubes in a kitchen towel and hitting them with a rolling pin.
For glassware, start with four coupe glasses and four rocks glasses. Coupes are more versatile than V-shaped martini glasses — they do not spill, they keep drinks cold longer, and they suit everything from sours to sparkling cocktails. Rocks glasses handle everything built or served over ice. That is all you need to begin.
Electric blenders unless you live in the tropics or have a dedicated frozen-drink obsession. Fancy speed pourers for bottles — they leak, they collect sticky residue, and they encourage over-pouring. Jiggers with four or five different measures printed on the sides — they are confusing and slow. Muddlers made of rubber or with textured bases — they destroy delicate herbs. And the complete bar set in a wooden stand. It is designed to be given as a gift, not used. Buy individual pieces of quality steel and wood. They will last longer, work better, and take up less space.
Start with the Core Four and a bottle of good whiskey. You can make an Old Fashioned, a Whiskey Sour, and a Manhattan tonight. Add tools as you add drinks to your repertoire, not before.