Orthodox women just try to look nicer on Shabbat, but dressing tzniut is an everyday thing:

- Skirts past the knees
- Shirts that cover up the collarbone
- Sleeves that cover the elbows
- If married: A shietal, snood, or head covering

Orthodox male attire/dress:

- The ‘dreadlocks’ you are refering to are really called Payot
You can learn about them here http://en.wikipedia.org/wiki/Payot
- Shtreimels http://en.wikipedia.org/wiki/Shtreimel
- Bekishes http://en.wikipedia.org/wiki/Bekishe
- Gartels http://en.wikipedia.org/wiki/Gartel
References :
~was raised as a modern orthodox Jew

Jewish women also do not wear anything special for prayer. We dress modestly, covering our arms until past the elbows, wearing skirts covering the knees, and married women covering the hair with a wig, turban, or hat. Again, this is regular everyday attire, not special for "worship."

Like Einav states, some less religious Jews will dress more like everyone else, but will dress more modestly to enter a synagogue. But again, this is out of respect for a house of worship, and not point to the actual worship.
References :
Orthodox Jew