One quick clarification on some terminology. (I'm staying away from things like plant varieties and sticking to the mainstream ones...)
Copyright: Protection given to the author or creator of an original work. This includes literary works, music, photographs, movies, computer software and a host of other things. It is my understanding that Copyright rights can be secured by simply stating that they are claimed. Use of the copyright symbol © being one common and widely recognised indicator.
Patent: Protection for an apparatus, based on how it works. That is, involving the engineering, chemistry, materials or other technical aspects of some invention that does something in a new way.
Registered Design: (Called a Design Patent in the USA) Protection for a design - it is simply based on how something looks. (As with a patent, the way something looks must be new, too.) For example, a Coca Cola bottle could not be protected under a patent, because it doesn't DO anything new, but the shape of it can be protected by registering the design. The scale, usage or materials are irrelevant - so, with the design protected, anyone who makes a keychain attachment or a 60 storey building in the shape of a protected design will need permission to do so.
Patents and Registered Designs must be registered with the official authority before protection is in force. At that time, the 'registered' symbol: ® can be used to indicate this has occurred - and it can only be used once the design or patent has been registered.
Trademarks: As discussed above - Words or letters or a symbol or a combination of these to identify a business and/or a product. The rules for protection of trademarks are a bit more involved than for Patents and Designs.....
The simplest and certainly the safe way is to register it, as with Patents and Designs. That way, you have an official reference point - and that can be extremely valuable.
But you don't have to....
By simply using a name or symbol in the normal course of business, so that customers come to associate that name or symbol with a particular business and/or a particular product then that name and/or symbol is, in fact, a trademark - through its usage. Such a trademark IS defendable in court if challenged or infringed upon by a competitor - but it requires the person claiming prior use to prove their case. Without a trademark being registered, that means finding any and all evidence to support this - the old family photo album with a dated picture of 'Grandad's old shop' could be just one of the things that would help. It's going to be hard work.
The next thing someone can do is put the letters ™ next to their trademark. You do not need to register anything to use this - just put it up anytime you want to. This is simply telling everybody "This is my trademark", with the implication being that you will protect it. However, it doesn't really offer you anything if you have to defend it in court - you still have to provide the proof of your claim over it. Back to the photo album, old newspapers and the business archives.....
Much better to just register your trademark, then there is little argument! This also lets others know you have such a trademark so they don't inadvertently try using the same or a similar one!
One last thing about trademarks is that they are separated into classes. Without going into the details, it allows the same trademark to be used for different businesses, services or products - as long as there is no potential for confusion. For example Pioneer is used for concrete, coaches and electronic equipment. There is no problem with this, since there is no confusion.
Remember, all of these 'Intellectual Property' protection mechanisms are meant for one thing - to allow the person who put in all the hard yards in creating something of value to gain some benefit from that effort.
I know Bill Gates might not need it these days, but he was instrumental in bringing us to where we are today. (Yeah, OK, I haven't forgotten Steve Jobs!)