There are several tricks to update fabric blinds, and the most foolproof is the use of starched fabric. Pick a fabric you like or that matches your new design scheme. Measure the width and length of the vertical blinds' slats. Divide your fabric according to this size and starch them. Starching fabrics make them more dirt-resistant. Insert these on the slats when they are dried, and you got yourself a cheaper alternative to branded fabric replacements. One useful and practical tip if you intend to use this method: pre-shrunk your fabric by soaking it in water and drying it. Your fabric could shrink during the starching and ruin your measurements. A less tedious fabric solution which would work with any blinds is draping the blinds with a sheer curtain or cloth. It'll still allow the light in, while giving your blinds an ethereal and fresh look.
If there is too much dirt on your blinds, inserting fabric or adding sheers won't work. Clean vertical blinds as clean as they could possibly be and dry thoroughly. This trick will change the appearance or design of the blinds so choose a wallpaper design that is classic and would go well with most themes. After choosing a wallpaper, measure the width and length of the vertical blinds' slats and divide the paper accordingly. Stick the paper strips to your blinds by using "Wonder Under" or some paste and glue. Use a brush to put on the glue evenly and a rolling pin to prevent air bubbles from forming. Using dyes is a tricky process because it uses water which could deform the blinds. But they do give a nice tint effect to the color. The trick is to dye-brush the slats and not soaking them in dye pools. This way, the amount of water is reduced considerably.
Vertical blinds are also a great opportunity to exercise creativity. Spray painting and airbrushing blinds create a different texture and feel from ordinary paint jobs. The variety of paint textures available today gives you a wide range of choices to experiment. Adding patterns through stamps and sponges is also a creative trick. No matter which method you choose, you'll end up with fresh looking, updated, and stylish blinds for the fraction of the cost of buying new sets of designer blinds.