Since your question does not provide many details of your world, I will focus on general principles that can be used to develop clothing for your project.
These five factors will influence clothing and its styles (in order of importance):
Climate is the most decisive factor because some climates may require clothing and some not. For example, if your species live in zones that are too cold for them to survive without coverings, they will develop clothing. Likewise, if the climate is optimal (not too hot, not too cold, not too wet, not too dry, etc.) there may be no need for clothing at all and it will not appear.
Climate also informs what types of fabric to use and how to wear clothing. For example, it is advisable to wear layered clothing (to trap air between layers) in the extreme cold. Similar considerations should be made for hot weather. Apparently, colour does not matter for hot weather, but weave (weight of the fabric and its pattern) and cut (loose or tight-fitting clothes) do (I vaguely remember that I read somewhere that black-white summer clothing debate is complicated and the best colour and style combination depends on wearer being in shade or exposed to direct sun, humidity, and the presence of wind. Unfortunately, I cannot find the link.).
The technological level determines what materials are available and how they can be processed. For example, pre-industrial societies will have access only to natural materials (plant fibre, leather, fur, and alike) while technologically developed societies may be able to produce synthetic fibres (polyester, nylon, and alike).
Technological level affects types of available fabrics. Fabrics can be woven, knitted, or non-woven. In addition to different manufacturing processes fabrics can have different patterns which are dependent on available technologies. For example, brocades require rather advanced looms.
Processing goes beyond fabric creation. It also includes clothing-making techniques. For example, corsets are impossible in Stone Age (they require knowledge of specialised measuring, cutting, and sewing techniques in addition to special fabrics and sewing notions like corset ribs). Another important aspect is that most of the clothing in the pre-industrial world was tailored to individuals (as opposed to the prevalence of ready-to-wear garments of today). One of the first mass-produced clothes were military uniforms (1812).
Technology will also affect dyeing, embellishments, and accessories. For example, many lighter shades of blue would be very expensive and/or unavailable in pre-industrial societies. Embellishments are decorative elements such as embroidery, lace, frills, ribbons, buttons, and so on. Buttons are easy to make and they appeared very early in history. However, they became functional only in the 13th century. Accessories will reflect everyday needs and habits. (Take a look at these stunning lice combs!)
- Available materials
Availability of materials depends on climate and technology. Here is the list of the most used fibres in our world and another list of fabrics made of these fibres and their properties.
If I am not mistaken, historically the most used materials were fur, leather, wool, flax (linen), hemp, cotton, and silk. You can start with the history of clothing and textile to see specific examples of uses and styles.
There are also some rare exotic materials like sea silk. They can be used to make items displaying high status, e.g. Emperor's robes.
- Culture and Society
Culture, social norms, and local laws and traditions will dictate styles more than anything else. However, they may also restrict the use of specific fabrics or materials. For example, there can be luxury laws that prohibit the use of expensive garments (rare fabrics, jewels, gold and silver threads, etc.) by the lower classes.
It is important to remember that while culture and society may have lots of weird requirements for garments, the utility will be rarely compromised. Nobility may use very restrictive and impractical clothing but these cumbersome outfits serve a purpose -- to demonstrate the high social status. Peasant clothing (excluding garments for special occasions like weddings, funerals, and various celebrations) will always be practical and adapted to the local climate and predominant activities.
No trade means that only local materials and technologies will be used. Styles will also be very homogenous and change slowly. Fast fashion is only possible in a globalised industrialised world where garments can be manufactured cheaply and fast. Historically clothing was not cheap and many items were passed down from one family member to another.
If trade exists, trade hubs will have a wider range of styles and fabrics. Remote and poor regions may not be affected if the trade is chiefly focused on luxury items. However, it is also possible that cheap fibres or clothes will be imported and become the common choice for the lower classes (as it is now with cheap clothing and fabrics imported to Europe and North America from less developed countries). Imported materials also can fully replace local materials if they are sufficiently cheap and abundant (this is less likely to happen in societies at low technological levels).