Downtown Tijuana is referred to as the Zona Centro. It includes Revolucion Avenue, which is the main tourist drag. It is not considered by locals and tourists alike as a nice part of Tijuana, though there are some nice parts that surround it, and efforts to make an welcoming urban space. As downtowns in USA are often considered run down, Tijuana is no different. You can expect to pay tourist prices anywhere in the downtown zone, except perhaps in chain stores.
For about 8 blocks, Revolucion is lined with shops, bars, and restaurants, many aimed at tourists. This is what most day-trippers to Tijuana experience, and it should go without saying that the entire Downtown is not representative of Tijuana, which is highly suburbanized, and certainly not of Mexico, however it is downtown "Centro" of Tijuana.
Many stores are oriented towards baggage, trinkets, jewelry, dental, optical, beauty, clothing, and the like.
There are some nice parts within downtown Tijuana, such as an art scene with galleries, and even wine tasting, group dancing, and the like, but one must look inside plazas to find them. Events such as classic car shows and animals for children do show a soft side of Tijuana's core, but certainly won't be found at midnite.
Constitucion Avenue, one block west of Revolucion, is a busy downtown street but without the nightclubs and pestering shopsowners. However it is hardly an authentic picture of Tijuana nor Mexico, its more a collection of utilitarian urban small businesses. Visitors should be careful (or aware) of walking too far north on this street or even Revolucion, best not to go below Juarez (Segunda) as it will abruptly lead you into the “red light” district.
Despite downtown's grimyness and occasional chic, it is a convenient spot, with some dirt cheap lodging, 24 hour convenience stores like Oxxo, Extra, and 7-11, numerous supermarkets, 24 hour public transport to all parts of the city and even Rosarito, and proximity to nicer areas of town.
The rest of Downtown tends to be gritty and grimy, a mix of brothels, auto repair, run down short stay hotels, utilitarian shops, and sex tourism oriented except the wonderfully nice smelling flower market area, which ironically is a block from the foul smelling fisheries area. The south end of Downtown towards blocks 10 and beyond become progressively cleaner and blend into a 24 hour and upper class neighborhood along Agua Caliente, then its climbs into the hills, with many upscale and trendy cafes and bars on Brazil Street.
From San Diego, cross the San Ysidro border, and to your right hand side, walk toward the arch all along the pedestrian street: The arch is located at Avenida Revolución and Primer Callejón Z. It takes less than 15 minutes. There are enough signs to direct you: You can’t miss it! At the arch, go to your left, southbound, and enjoy your walk along the Avenue.
Alternatively you can take a taxi:
The traditional Yellow Cabs are just across the border, on their own commuter spot. Many cab drivers wearing a yellow & black uniform will be hosting you. Most of them speak English and take US dollars. Make sure to negotiate the fare before starting the ride. $3 US will be expected to “Avenida Revolución, Zona Centro”. You can arrange the same cab picks you up later with no extra charge.
Street Cabs are outside the commuter spot. These are white cars with a red stripe and labeled as “Libre” (Cab). They usually park in line along the street and some of them have a dispatcher who has written rates. Usually, their rates are almost half of the yellow cabs´ and take US dollars as well. Make sure to confirm the fare before starting the ride and to have the exact amount as they hey carry no change.
In San Ysidro, catch the Mexicoach that will take you to the bus station in the Zona Centro in the middle of the the Avenida Revolución, the heart of the Zona Centro Distiect.
There are some good shops along Revolucion but mostly they are little more than cheesy souvenir shops. There are a few "fixed price" shops as you walk south on Revolucion. "Precios fijos" no games. And the people are nice. The ladies in colorful native clothing with the little stands often have awesone painted ceramics. Just remember to haggle. The same ceramics on the "Avenida" in shops will cost at least twice as much.
Restaurants vary in quality. Tourist traps are usually easy to spot. These will be overpriced, but may serve good food. Then again true Mexican prices are hard to find in downtown other than big chain stores, as what may seem like a great deal is still overpriced for the average Mexican.
The bars on Revolucion are often packed with people from the US. The drinking age in Tijuana is 18, compared to 21 in the US, so many young people visit Tijuana to party. Revolucion is also lined with strip bars, and it is not always obvious from the outside if it is a regular bar or a strip bar, so enter with caution.
If 2 for 1 is advertised, you may not split it with your friend. Even if the waiter plays dumb and only brings two drinks, as soon as you take the first sip, he comes with the other 2 and happily says "2 for 1!!!!"
If someone grabs you and starts pouring tequila down your throat that is not free either.
Use common sense. To stay safe, avoid establishments selling drugs, sex, or anything illegal. Avoid people who try to befriend you to sell you something, or strike up conversation unsolicited in English.
If you see the ubiquitous indigenous women with lots of kids, understand that they are among the most discriminated people on the planet and face extreme hardships that is far beyond the scope of wikitravel to describe in detail. Though they come to the city in packs, if they or their children ask you for money and you sincerely do not want to give, you may just ignore them or even give a curt "NO" if you are hassled. Note that financial assistance is sincerely appreciated but may open the door to endless begging. If that bothers you adjust your behavior accordingly.