For women in Italy, the clothing of the 1530s was characterized by fairly tight bodices, full attached skirts, and sleeves poufy at the top and tight at the bottom. Bands of a contrasting color seem to be a popular method of decoration. Underneath, ladies wore a camicia (a undergarment with lots of fabric, in the style typically thought of as “renaissance”), and often also wore a partlet, which may be completely tucked into (or tied) the bodice or sometimes over the bodice
(sometimes tied under the arms, or pinned to the bodice then). Headwear seems to often take a
“roll” style around the head, sometimes of quite fantastic proportions!
Portraiture, by this time, tended toward the naturalistic, so many many details about the clothing can be determined from close examination of the portraits. Always try to find the biggest, highest resolution images possible – many of these paintings are quite large, even full-size!
To the right is a portrait by Lorenzo Lotto, who was painting in the Venetian area when this portrait was done, between 1528 and 1530, showing several of these characteristics. Her bodice, unlike most of those during the 1530s, is spiral-laced up the front, and the opening extends into the skirt. The sleeves appear to be attached entirely, and the lower sleeves have slits near the elbow (probably to allow motion). Under the gown, she is wearing a camicia which has a flat neckband, and a ruffled cuff at the wrists. At the slits and ends of the sleeves, there is a fluffy lining visible, possibly some kind of fur.
Over her left shoulder is a gauzy partlet, and the rest of it is hanging behind her right shoulder.
Also, there is some horizontal wrinkling near the waist, which may indicate that there is no corset under it.
Next on the right is a painting by Agnolo Bronzino, dated between 1530 and 1532 of an unnamed lady in green. Bronzino was the official court painter at the
Medici court of Cosimo I, and painted many Florentine nobles. It shows many of the same general characteristics, but it clearly does not lace up the front – the lacing may be on the side or the side back. Here, the whole main gown is of green, while the bands and lower sleeves are of white. The lower sleeves are slashed, and the edge of the bodice is trimmed in the same white as the bands. The high-necked garmet is probably a partlet, not a shirt, and is decorated with blackwork.

Again on the right is a painting by Jacopo Pontermo, also from 1532, of an unnamed lady in red with a small dog or puppy. Again, we have the same tight, bodice area, with a full skirt and full upper sleeves. Here the lower sleeves are made of a black velvet. Like the previous one, she is wearing a high-necked, very full garment that is probably a partlet, fastened with buttons. Most partlets seem to either not fasten closed, or do so with ties, so this one is interesting. She also is wearing a belt or girdle and holds a rosary on her lap.
Unfortunately, we can’t see where this one closes, either.
On the left is a portrait by Pierfrancesco di Jacopo
Foschi, another painter of the Florentine school, which was done some time between 1530 and 1535. Here is a clear counter-example to those who exclaim that pink isn’t historically correct – this lady is clearly dressed in pink, with contrasting bands of black, fur lower sleeves, and a long, hanging girdle ending in a tassel. Her highnecked, embroidered partlet ties shut at the neck
For men, it’s much more difficult to determine – the fashion for men’s portraits seems to be to wear a heavy black coat over all the clothing, making details difficult to see. However, the most likely garb would be a fairly close fitting doublet, either buttoned or tied in the front, with attached sleeves, worn over a collared shirt fastened at the neck. The type of pants is also difficult to determine, but some sort of shorter pants
(poufy or not) and then hose seem likely.
On the right, another painting by Jacopo Pontermo, from some time in the 1530s of a young halberdier.
This is one of the few paintings I’ve found where the person isn’t wearing a coat, so we can see the doublet, which has a slight collar to it, full sleeves, and is buttoned up the front. The pants seem to tie shut, but it’s difficult to tell how they’re fashioned.

To the right is another martial portrait, by Dosso Dossi, also dated to the 1530s, from Ferrara. There is an odd interaction with the light, making some of the armor difficult to view. However, it’s possible to see that the undersleeves are either part of a full under garment, or attach to the doublet inside the slashed cap sleeves.
Also, his shirt ties at the neck, and the doublet is open at the front with no visible buttons or button holes.
The detail is difficult to see in these other pictures, because they are primarily wearing black, but more can be seen in the full-size images.
Left is another portrait by Lorenzo Lotto, dated to
1530. This one is most interesting because it is ¾ length, instead of just the chest and up. Thus, we can see that the black coat he is wearing has very large sleeves and is tied shut around the waist with a black sash or cord. Just below the waist, there is a black codpiece visible as well, and below the coat, there are garters, presumably holding up his hose.
Back to the right, the black on black buttons of the doublet are barely visible in this 1535 painting (again by Lorenzo Lotto) of an architect. In this painting, he appears to be wearing his coat just over his shoulders, like a cape, showing the doublet.
This one seems to have longer skirts, like the one above, and the sleeves are part of the doublet. Like several of the men above, he is wearing a flat cap.
Left, another 1535 portrait by Lorenzo Lotto, in which the pink doublet is visible under the coat, with buttons.
It is again worn over a shirt – visible at neck and wrists. It appears that the buttons are made of the same material as the doublet.

Other References:
Here are some links to pictures and instructions on creating clothing suitable for the 1530s in
Italy.
The Realm of Venus: http://www.renaissancewoman.net/realmofvenus/
Many pictures, specifically focussed on Venice, but many things apply to other parts of Italy, also a great section on making camicias: http://www.renaissancewoman.net/realmofvenus/seamstress/camiciahowto.htm
Festive Attyre
Florentine portraits 1525 – 1550: http://www.festiveattyre.com/research/secondflor/portfolio.html
A Florentine dress diary : http://www.festiveattyre.com/research/diary/diary.html
The Zen of Spiral Lacing: http://www.festiveattyre.com/research/lacing/lacing.html
The Renaissance Tailor: http://www.vertetsable.com/
Not necessarily Italian, but very helpful for techniques – check out the demos section : http://www.vertetsable.com/demos_main.htm
Italian Renaissance Gown Construction: http://homepages.wmich.edu/~rowen/renbk/rendressbook.html
Simple directions for making your own Italian Renaissance gown
Wikimedia Commons: http://commons.wikimedia.org/wiki/Category:Italian_Renaissance_painters
Some really good scans of paintings.
Recreating History: The chemise: http://www.reconstructinghistory.com/beginners/chemise.html
Another easy pattern for the chemise or camicia