There have been requests on some country/city forums for information regarding hiring tourist guides.
Many countries (in Europe especially) only allow properly trained, registered guides to work as guides.
In Italy, only registered, authorised tourist guides can be used - you'll be in trouble if you use anyone else (don't take those who try to pick you up in the street) - as it's illegal to use unauthorised guides walking or on a coach and the police do check. There is a list of authorised, qualified, tourist guides registered with each province (e.g. the Province of Messina for Taormina, in Sicily at the official website ww.guidemessina.it ). They have guides who speak other languages too - and these will have passed examinations in the vocabulary required to speak about such things as architecture - and in fluency for the language. For English - look for 'inglese' in the bit after the individual guide's address etc.
In England there is no law prohibiting anyone being a tourist guide, and there are some perfectly well informed, good, though not registered or trained, guides with some tour companies that just haven't employed the registered ones for whatever reason. But it is wise anywhere - if you have no personal recommendation - to use a properly trained guide with local knowledge and a cultured/educated background. In the UK the Institute of Tourist Guiding and the Blue Badge Tourist Guides websites will provide full details. The Blue Badge is the qualification of the UK's professional, registered tourist guides. They may be authors, actors, historians, police-men, university lecturers, interpreters etc. but they have also been specifically trained to be a tourist guide - and come from all walks of life. The Blue Badge training normally lasts eighteen months with eight rigorous written and practical examinations plus foreign language examinations to ensure fluency and vocabulary (e.g. for architecture) and endorsement examinations for areas of particular interest - e.g. a city or a cathedral.
Nevertheless, it is quite true you can never be sure how good the guide is going to be (whether Blue Badge or not) until you���ve been on the tour. So it���s worth checking on Trip advisor for recommendations, particularly if the tour company concerned doesn���t mention their guides��� qualifications. They are usually only too pleased to boast that they employ Blue Badge Registered Guides. You should bear in mind that a Blue Badge guide has to keep up the image and reputation of the Blue Badge and it would be unlikely that you���d get a dud.
In any country, the local tourism office may also have lists of free tours being given by qualified / registered guides - if there's only a few of you. Hiring a qualified, registered, guide for a small group can be expensive - depends on how much you're willing to spend !
To give you an idea of the cost, in the UK - the Institute of Tourist Guiding registered Blue Badge Guides charge in the region of GBP58 to GBP65 for two hours in a foreign language. Too much for one tourist - but if there's a group of you it will make it quite reasonable. Obviously, this cost is usually split between fiftytwo passengers on a tour bus - or twentyfive passengers on foot (the maximum number of tourists allowed per guide on foot - safety/insurance reasons).
In all these cases - with registered guides, You will have a knowledgeable, historically accurate tour - by a trained guide who knows the area really well and will never speak with his/her back to you (it's ridiculous to pay for a guide you can't hear !) .
Otherwise - I'm afraid it's a case of 'self-education' - you'll have to buy a guide book !!!! I've found the DK pictorial type guidebook very easy to read - with little maps of each area or street they describe. If you take the trouble to read some books about the area you're visiting, you'll get more pleasure from your visit. But at least, pick up some leaflets from the local tourist offices, or the country's tourist board before you leave your home country - that's why they're there. Most will send you information free of charge if you bother to contact them in time, before you leave home.
If you're only in a particular place for a day - perhaps you should just spend the time having a relaxed overview - have lunch in a nice restaurant the locals use - a quick look at a couple of key sights that particularly interest you, including one 'panoramic view point' , and that aren't too far to walk/bus to. Then, sit back with an iced coffee, or a local drink, soak up the atmosphere, and plan your next holiday in that area ! I wish you all the holidays of your dreams ! Nolana