What tools do you need

Common items you need for miniatures are 

• a cutting mat, 
• a craft knife- exacto, scapel blade, stanley knife. Many replacement new blades for your knife. Essential. If the blade is blunt, one you risk hurting yourself, two its hard work cutting.
• glue. 1-White glue known as PVA. I prefer exterior PVA. there are other types. Interior, Gorilla, weldbond, ... 2-Tacky Glue- this is thick PVA. 3- Paper glue, UHU style. Any brand works. 4-Fabric Glue if you are going to use material. 5- Superglue, also known as Cyanoacrylates.
• toothpicks-many uses, but mostly for applying glue.
• sandpaper- a variety of grits. I use 120 through to 800.
• clamps-can be anything from pegs, masking tape, bulldog clips to fancy carpenter clamps, small clothespins or clamps. Something to hold things together while glue dries
• paint brushes of various sizes
• emery boards
• Q-tips (Cotton-buds)
• tweezers- fine point and blunt ended.
• plastic bags to keep your project in, also square containers for furniture.
• notebook and pencils
• 12" and 6" steel (corkback-if you can find them) rulers
• glue spreader (old credit card)
• wax paper
• squaring jig or lego
• scissors (paper and fabric)
• damp cloth or wipes
• masking/scotch tape
• pins, needles, thread

From this you can expand into many different tools and items. Powertools are a whole new discussion.