Ah, the topic of brands... one of my favorites, and one that is often controversial. Why? Because people will always have disagreements about brands, whether it be on quality, style, reputation, whatever. I'll attempt to swing at this curveball though, and I hope it doesn't anger too many of you.
I think brand names are a wonderful proxy for discerning quality distinctions in clothing. I swear by certain brands due to their quality (eg: Tellason and Gitman Vintage in the pic above), and will always trust that they will make a genuinely great product. However, I also think that brand names can often be over-emphasized, bandwagoned, and taken way too far. For example, I know many people who will immediately dismiss the quality of companies like the Gap or J. Crew because they generally make mass-produced articles of clothing at less than optimal quality-control. Before moving forward, let me tell you right now, I've bought pieces from both Gap and J.Crew that have exceeded my highest expectations. And though it's not always the case, I'll often find deals that will blow away any competition at those price points: Thomas Mason shirt from J.Crew for $35? I'll take it anyday.
Also, in the other direction, people will endlessly praise companies like Lanvin or Oxxford for their excellence in quality. However, I've had a pair of Lanvin pants tear apart on me, and have a friend whose Oxxford shirt lost two buttons in the first day of wear.
Am I saying that J. Crew makes a better product than Lanvin? Absolutely not. In fact, I can confidently say that Lanvin is at another level in terms of clothing quality (I mean just look at the price difference). However, what I am trying to say is that brands are not static, and there will always be quality changes that come with following a brand, up or down. Thus, it doesn't make sense to rely solely on brand when making a decision on what to buy.
Now that I've gotten that giant caveat out of the way, I will say that brands can at least make it easier for you when shopping for clothes. All brands have reputations to uphold, and need to stick to a certain level of quality in order to maintain those reputations. Thus, you can trust certain brands that have held the test of time, or been deemed by the general public as high in quality. This way, when you enter a mall and you have 100 brands in front of you, you'll be able to at least start weeding out what you'll look through and what you won't, based on brands.
I wouldn't advise that you put all your eggs in the brand basket though. Nothing beats going into stores and actually feeling fabrics, wearing the clothes and moving with it, checking the construction, etc. If you find a piece that catches your eye, don't dismiss just based on brand. Go up to the piece and check it out! From there, make sure that the quality is high.
So what are good indicators of high quality garments?
1. Material. Is it made of more natural materials like 100% leather, cotton, silk, or wool? Or is the material fully/partially man-made (spandex, rayon, polyester, etc.)? If possible, I would recommend sticking to more natural materials. Not bulletproof in determining quality, but it's a start.
Also, does the material look and feel solid? Hold the garment against a light, and see if the thickness of the material is consistent throughout. Buttons and zippers matter too (horn buttons > plastic buttons, zippers can feel more solid on some rather than others).
2. Construction. Take for example suits. Some suits may look amazing and have a great fabric, but aren't constructed in a way that deems them high quality. They may be fused together in the inside and the outside by glue, rather than canvassed fully to help remain its organic shape. Maybe the seams on a shirt or jacket are at points like the elbow, which might not make the piece as durable due to the way we move. Are buttons put together well? Are shoe soles stitched or glued? Inspect items as best as you can to check on the constructional integrity.
3. Made in ____. This can sometimes be misleading, but it is indeed important to check. Products made in the U.S. or countries in Europe are often more reliable in quality than those made in Southeast Asia and China. This isn't ALWAYS the case, but it correlates quite often due to the cost of manufacturing. In reality, it just costs more to produce things domestically, so the quality better match the price.
4. Style. Don't forget that we buy clothing so we can look good. It's not solely just to feel great, since if that were the case, we would all just wear blankets of cashmere and fur exclusively. If a piece of clothing is styled well, there is a higher likelihood of the brand fitting you better. Look at the styles, patterns, and designs, and ask yourself if you find them especially appealing. For example, one of my favorite brands is Theory. Not for the material quality, since that can sometimes be shoddy, but because all Theory products seem to fit me down to a T.
So in all, definitely identify the brands you feel are great quality and fit you well. You can use these brands as go-tos and make the process much easier when shopping. However, try not be a brand-whore, and think less of others due to the brands they wear. There are some fine quality garments in virtually all clothing brands, and until you feel & wear the clothing yourself, you shouldn't make rash judgements on the quality that certain brands can offer. Check for yourself, and buy things that are high in QUALITY, not just BRAND.