You may have some diarrhea issues adjusting to the foods and liquids in Venezuela. You should preferably buy bottled water and not drink from the tap, but iced drinks and salads are generally fine depending on the water supply quality of your native country. Be careful with expired foods and cheeses that are many days old.You usually find street vendors by highways, who sell food and who don't always have much knowledge of hygienic food handling practices. Use common sense when selecting what to eat in the street. Mind, that fresh food and mayonnaise may go bad fast due to the local climate.
Venezuela has its fair share of poverty and crime. Venezuela has one of the highest homicide rates worldwide (http://en.wikipedia.org/wiki/List_of_countries_by_murder_rate). It is necessary to be vigilant when in crowded cities, as pickpockets and muggers may be around. Most sections of large cities are not safe to walk at night. Stay in populated areas. Always travel by vehicle at night. The outskirts of many cities are very poor and crime-ridden, and are not appropriate for tourists. When in doubt, ask local inhabitants or taxi drivers whether an area is safe or not. In general, if one looks like a presumably wealthy tourist, these sections of town should be avoided. It is advisable not to wear expensive jewelry or watches. Take care with taking pictures and unfolding maps in crowds. Pretend you know where you are going even if you aren't sure.
Always ride on a legal taxi Yellow plates. The white plates taxis are not legal and may be dangerous.
Additionally, one must be wary of corrupt officials police and National Guard. Some officials may demand bribes or otherwise extort travelers. Keep watch of your belongings at all times. Despite all these recommendations, one is usually quite safe in Venezuela if they apply a little common sense, and avoid looking overly wealthy when traveling. Women with big purses are recommended not to walk around alone. Tourists should avoid walking long distances in the towns and cities unless you know where you are going. Where possible arrange vehicle transport. It is not advisable for female tourists to walk through poor areas or shanty towns without a local guide. It is greater risk of rape or sexual assault if they walk through these areas.
Above all, when you are in Venezuela it is very important to use common sense. If you follow the right precautions, you'll probably have no problem. Don't look at anybody the wrong way, and don't look too wealthy.
In the sad event you do get mugged, by all means don't even try to put up resistance and avoid eye contact, most muggers in Venezuela carry firearms and don't hesitate to shoot at the slightest provocation, keep calm and give the mugger whatever he wants, failure to do so is quite often deadly, also, reporting a mugging to the police is seldom worth the trouble, it's best to forget it as muggers are only rarely caught.
Despite all the issues with insecurity, you may avoid most problems by either staying in the touristic areas or visiting the less touristic areas with someone that lives in the country.
Also, Venezuela has an interesting policy towards cannabis. You may possess up to 20gr, but be forewarned that anything more can get you thrown in prison for a long time. Even though this policy is quite liberal by American or British standards, you should keep all cannabis use private, if just to not have unwanted attention drawn towards you.
Avoid long distance car traveling at night, since many highways are insecure then. Venezuelans are usually ready to help you if you have a problem. However, they probably won't dare to stop for you in the dark, as they would risk to be assaulted with good cause.
by mail
Venezuela's state-owned postal is slow, unpredictable and not widely used. Postal offices are few and far between, although they are still probably your best bet for sending postcards back home. For mailing within Venezuela, courier services such as MRW, Domesa and Zoom are the most popular. These usually guarantee next day delivery!
respect
Most Venezuelans are laid-back regarding racial issues, since white or creole persons blend naturally with natives and Afro-Venezuelans in everyday life education, living, politics, marriage. So the word "negro" can be used regardless of who's saying it, or who is being referred to in this way. Expressions like "negrito" or "mi negro" are often used as a term of endearment. You could hear someone calling "negra" to a woman, regardless of the race of the person. And in general, Afro-Venezuelans don't find it offensive, as they are simply variations on the Spanish word for "black". Similarly, don't be offended if someone calls you "flaco" thin or "gordo" fat as these may also be used fairly indiscriminately, and often as a term of friendliness.
Differences between Brits, Americans, or Europeans are not perceived by most Venezuelans. Hence, you can expect to be called "gringo" even if you are, say, Russian. Don't let this offend you as a non Spanish-speaking visitor.
Venezuelans, like Colombians and Panamanians, have a very amusing way of pointing to objects by pouting their lips and lifting their chin, so don't assume that people are blowing kisses to you when you ask for directions.
Another important point to be kept in mind is that the Venezuelan society is severely split between "Chavistas" those who support President Chavez and "Anti-Chavistas" those who oppose to him, so it is strongly advisable not to talk about him and/or his politics unless you are sure on which side your Venezuelan friends are.
by net
Internet cafes, often incorporated in the above-mentioned 'communication centers' are increasingly common, and even small towns usually have at least one spot with more or less decent connections.
by phone
Venezuela has international country telephone code 58 and three-digit area codes plus an initial '0', and phone numbers are seven digits long.
Area codes beginning with '04' - e.g. 0412, 0414, 0416 - are mobile phones, while area codes beginning '02' - e.g. 0212 Caracas, 0261 Maracaibo are land lines.
A single emergency number 171 is used in most of the country for police, ambulance and firefighters.
The international phone number format for Venezuela is +58-area code without '0'-phone number
To dial to another area code: area code starting with '0'-phone number
To dial to another country: 00-country code-area code-phone number
Directory enquiries/information in spanish: 113
Emergency service for mobile phones: in spanish: 911 Movistar, 112 Digitel, *1 Movilnet
Public payphones use prepaid cards which cannot be recharged but are easily available in shopping centers, gas stations, kiosks, etc. Phone boxes are common in the cities and do not accept coins. The vast majority are operated by the former state monopoly, CANTV, although some boxes operated by Digitel or Movistar do exist, particularly in remote areas. CANTV prepaid cards can be used only in their booths.
More popular today are the ubiquitous 'communication centers' or clusters of phone booths located inside metro stations, malls, or like a normal store in the street. Most of these comunication centers are operated either by CANTV or Movistar, and offer generally cheap phone calls from a normal phone in comfortable booths equipped with a seat. A log is made of all your calls and you pay when exiting the store.
Many street vendors or buhoneros also offer phone calls from portable antenna-based land lines set up at improvised stalls. Callers are charged by the minute.