First, register by completing an online registration form.
You may be asked for your credit or debit card details during the sign-up process, but this is usually just to verify your identity.
Once your account is set up, you can begin making the most of your auction site.
Auction sites work by registered members bidding on an item in a chance to 'win' or buy the item.
Proxy bidding is when an auction site places bids on your behalf, and with your initial permission.
All you have to do is to enter the lowest price that you are willing to pay for an item and then the site will make a series of incremental bids on your behalf, up to your maximum bid.
Doing this means you could win an item for a price less than the absolute maximum you were prepared to bid, however if somebody else bids above your maximum specified amount, then you will lose the item.
For example, if the existing bid on an item is £1, but you do not want to sit by your computer as the clock ticks down, you can choose your maximum bid and the system will update the price in increments in hope of getting you the item at the lowest price.
If you successfully place the winning bid for an item then you will usually receive a confirmation via email.
It will then be down to yourself and the seller to arrange payment and delivery between you.
Selling an item on an auction site like eBay, will usually require making a listing for your item.
This can involve giving it a title, writing a detailed description of your item, adding a photograph, placing it in a category which includes similar items and deciding on the starting bid.
You will also have to enter the location of your item, decide how much to charge for delivery (or whether you will allow the buyer to collect it themselves) and your preferred method of payment.
If your item sells then it is down to you to organise payment and delivery with the successful buyer.
Do not worry if your item fails to sell, you will not be charged a valuation fee and you can always list it for free a second time as long as it sells the second time around.
It goes without saying that no matter how nice the buyer seems, you should never dispatch an item without receiving payment first.
Whenever you sell an item on sites like eBay, you could be charged an insertion fee when you list the item and a valuation fee if you successfully sell the item.
The insertion fee is based upon the price at which you wish bidding to start, while the valuation fee is based on a percentage of the price at which the item is sold.
There are also optional extras that could enhance your item's chances of selling, such as extra photos or a 'Buy it Now' feature which allows others to buy the item for a set price instead of through an auction.
You should also be aware that if your buyer pays you through a service such as PayPal, then you will also be charged a fee of between 1.4% and 3.4% of transaction plus 20p per transaction*.
* Deducted from PayPal account
You can list up to 20 items a month for free before paying any fees.
It is the same as with any business; reduce your overheads and sell at the best possible price to maximise your profits.
Here is our top tips of how you can apply those principles to the world of online auctions:
Try searching for misspelled words or even American spellings like 'color' instead of 'colour'. If people cannot find an item then they cannot bid on them and drive the price up.
Always take into account additional costs like delivery charges before bidding on an item.
Just because an item is on eBay, do not always assume that it is a bargain - always check the price elsewhere online.
Bid early* and you alert other buyers to your interest, forcing the price up.
With an estimated 15 million users, eBay is by far the most popular auction site on the web. Buying from a less popular site like eBid could help you pick up a bargain.
* Try using sniping software which waits until the very last seconds before making a bid on your behalf.
If you are just starting out, buy a few cheap items to build your feedback up - some buyers and sellers do not like dealing with newbies.
Finding things to sell on auction sites is not just limited to the contents of your cupboards or garage.
Brand-new items always sell better. If you receive an unwanted DVD or video game always leave them wrapped in their original cellophane packaging.
We all know that people love to buy brands. If you are selling Nike trainers or a Toshiba TV, make sure you mention it in your item's title.
Everyone knows someone who is an eBay whizz. Why not get them to sell your stuff for a cut of the profits?
List at times so that your auction ends when people are at home - Sunday afternoons or evenings and Mondays tend to be the busiest.
Take advantage of free listings days which sites like eBay often run at weekends.
Think like the buyer and use the words that people will search for in your item's title.
The lower your item's starting price is, the more likely you are to sell it.
Do your research - What have similar items sold for? What kind of descriptions sell? What keywords have successful sellers used in their titles?
Spell check your listing - you do not want someone else profiting from your mistake.
By knocking a penny off your £15.00 starting price and listing it as £14.99 instead you could save you on fees.
Avoid listing and valuation fees altogether by using a free classified ads service like Gumtree.
Be inventive, scour:
Car boot sales
1p auction sites
High street sales
Anything that offers you a margin when selling on for profit.
You can even snap up bargains on auction sites to sell on for an elevated price by adding a better description or image.
In closing, we would just like to provide you with a few dos and don'ts when it comes to auction site.
We cannot guarantee they will help you make your fortune, but they could be the difference between your item selling and suffering the ignominy of re-listing for the third time.
Do be honest when describing your item and include details of any damage.
Do use PayPal for a safe and convenient way to receive payment.
Do make sure you list your item in the right category.
Don't be tempted to overcharge for postage as it will put off buyers.
Don't use an out of focus, low-resolution photograph for your item.
Don't bother paying a reserve fee for your item - it puts buyers off.