1. Top stitching neckline or armhole: instead use facing and interfacing or preferably bias binding. Topstitching your clothes makes you look lazy to your clients and make the clothes look unpresentable.
2. Using the wrong interfacing or no interfacing: this is almost the same with the above point, interfacing gives clothes, especially jackets, support and makes them look fitted against the body. Also interfacing used for bands give your clothes a professional look.
3. Hand stitching: except for button holes and fixing buttons, I do not think it's advisable to handstitch your clothes. Imagine how terrible a dress or jacket will look if you hand stitched lining to it, unless you are exceptionally good at this, avoid it completely.
4. Skipping darts: darts are important in clothes, without them horizontal wrinkles will be forming everywhere. They tend to bring fitting to your clothes and bring out the right shape, eliminating any buldge that might want to form, they are that important, in fact, the only time you shouldnt use them is when you are working on extremely stretchy fabrics or clothes that are meant to be flared.
5. Using the wrong fabric for a particular design: imagine using a soft fabric for a cloth that's supposed to be firm and stiff or vice versa, like using a semi stretchy fabric for a leggings you get the idea?
6. Laying obvious designs in opposite directions: like laying stripes in vertical directions for the front part, then horizontal at the back, it makes it look as if you didn't know what you were doing while sewing. Instead stripes, patterns or obvious designs should be laid in the same direction.
7. Lack of pressing while sewing: the importance of well-pressed seams cannot be overemphasized, opt for pressing boards such as clapper boards or a good quality iron. Pressing as you sew avoids buldges and makes your clothes look good. Open all seams and press them opened, any hemming you do should also be pressed before stitching, press to make them completely flat.
8. Contrasting thread colour: the colour of your thread must match the colour of the garment you are making, don't use contrasting colours except you are trying to design the dress. If you don't have the exact colour, use colours that almost match. The closer the thread matches the fabric, the less noticeable it will be.
9. Using household scissors for cutting your fabric: invest in a pair of good scissors this might not look important to you but it's really necessary. They must be used for fabric cutting only, don't use them to cut paper or any household work, and don't use your household scissors for fabric cutting.
10. Not buying enough fabrics: this is especially important for beginners-Make sure that you have enough fabrics, managing fabrics is hazardous. You must always have extra to fall back on incase you make a cutting mistake.
I hope that we have learnt one or two things about sewing, other mistakes you could make are not taking correct measurements, having an out-of-order machine or even buying cheap clothes.
