Step 1: Pick a store you want to terrorise, and check it's opening and closing times carefully. Depending on your plans for the rest of the day, there are three optimal times for you to strike - when the store first opens (getting there early and waiting with undisguised impatience outside the door is key), during lunch hour (during a rush when some of the staff members have disappeared for lunch is reccommended) or, my personal favourite, five minutes before closing time.
Step 2: When greeted by a salesperson, you have two choices: ignore them completely, or respond with "just looking". Make sure you don't smile.
Step 3: If products in the store have price tags, you must ask a staff member the price of at least three items. Ask if there is a discount or special on each item.
Step 4: Pick an item they are obviously low on stock of. Ask if they have other colours. Then ask if they have other sizes. Ask if they have any more stock. Ask them how long it will be until more stock arrives. Ask them if they're "sure" they don't have the colour and the size you want. Ask them if they can get it in from another store. If they say yes, tell them you'll think about it.
Step 5: If you look at anything, make sure to talk incessantly to any staff member who has crossed your path. Tell them you're not sure about the size. Tell them you don't really like the colour. Read the price tag (or ask them to repeat it) and wince. Ask them to get you the size up. Ask them to get you the size down. Ask them to get you another colour. Ask them to get you the size up in another colour. Ask them to get you another colour, in the size down.
Step 6: If the staff member has to leave you at any time, scatter as many items around the store as possible, or re-hang/box etc. very badly and stash it under a shelf or behind a display.
At the till
Step 1: Drop your loot on the counter and don't say anything. Wander a meter or so away to 'look' at something else. If someone asks you if you are taking or discarding your items, make a noise somewhere in-between a yes and a no.
Step 2: When you eventually find your way back to the counter, do not make eye conact with the tillperson. If you do, don't smile.
Step 3: When they tell you the total, ask them for a discount. If they say no, ask them if they have a 'new' item, i.e not the one you tried on.
Step 4: Throw your cash/card down on the counter, do not hand it to the tillperson. If it is cash, make sure it has lots of fiddly bits of change that they have to count. If it's a card, do not tell them what account it is on. When they ask what account it is on, pause for at least five seconds (count in your head if necessary). Say "on the card". If they ask if that means credit or savings, pause another three seconds. Take your time entering your pin number, or if you're signing, cut them off when they ask you "pin number or sign".
Step 4: Whist your receipt is being printed, wander away again. Wait until they call you back to the till or someone brings your shopping to you.
Step 5: Do not make eye contact or say thankyou. Storm off to the front of the store, then stop, and spend another 5-10 minutes browsing.
Step 6: If you are really dedicated, you have two options. One is long-term and one is short-term.
Short-term: throw away the receipt, and go back a few days later to return or exchange your item. For bonuss points, wait until they've shut the door and are cashing up for the night, then bang on their closed door and tell them that "it's urgent", and if they tell you they can't process anything because they've turned off the computer, say, "Can't you just swap it for me now and put it through the computer in the morning?"
Long-term: keep the receipt and wait at least a week until outside the return/exchange period. Return with the item and attempt to exchange or return it.
On the phone
Step 1: When someone answers the phone (the usual format is "Hello,[shop name]
Step 2: Ask, "who is this?" When they repeat their name, ask "is this [store name]
Step 3: Tell them you're looking for an item, but make it something particularly vague, like "a brown belt" or "a red bag". This is especially reccommended if you are calling a specialty store which stocks 1-5 particular brands.
Step 4: If they ask you to clarify anything (such as the material, size or brand) repeat your initial description.
Step 5: If they make a suggestion, such as "were you looking for a brown leather belt for a man?" say "yes" and then stay silent.
Step 6: When they can't figure out what it is you're looking for (meaning you shot down all of their suggestions) ask to talk to someone else.
HAPPY RETAIL TERRORISING!