How to Shape Acrylic Nails
To shape acrylic nails at home, begin by trimming your nails to the length of your choice. Then, decide on what specific shape you want, like square, coffin-shaped, or round. For square nails, file just the tips of your nails. If you'd like coffin nails, which are squared-off at the ends, file the tip of your nails flat, then file the sides of each nail at a light angle. And if you want round nails, use an arc-like motion while filing them.
Reduce the length first. It is important to cut down the nail to your desired length before you begin to shape it. Otherwise you might shape your nails and then realize they are too long. You can either use a grinder to cut down the nail or use a file to reduce the length manually. Don't worry about the shape just yet. Just focus on getting the nail's length to where you want it to be. Thin out the nail. Your nail may be somewhat thick after you file it down and this can look unattractive. To improve the appearance of your nails, you can thin them out by grinding or filing away some of the nail's surface. You will need either a motorized nail grinder to slowly grind away some of the nail or a file to manually file away some of the nail. File or grind along the top of the acrylic, not underneath it. Use a curving motion as you file or grind away at the nail, but make sure to work in 1 direction only. Don't turn the grinder around halfway through. Make sure that you only grind along the free edge of the nail. Do not try to grind the acrylic nail over the edge where the nail is attached to your natural nail. This will weaken the nail and increase the chances that it will break. Use a nail file for fine tuning the edges. After you have finished thinning the nail, you can use a nail file to fine tune the edges of your nails. For example if you notice any rough spots along the surface or the edges of the nail, then use a fine grit nail file to gently smooth them out. A metal file or emery board works best for filing acrylic nails. Make sure that you only move the nail file in 1 direction. Do not use a back and forth motion. File down the tips for square nails. Square nails are good starting point for most nail shapes, but they might not look good on everyone. If you have short and/or wide nail beds, then wearing square nails might make your nails look short and stubby. However, you might want to try out square tips first, since you can easily change this shape into something else. To get square tips, simple file the tips of your nails only. Keep filing straight across the top edge of your acrylics until they are in a square shape. For pointy nails, you may need to remove a lot of length to get a square shape. Then, round out the corners slightly so that you eliminate the sharp corners while keeping the square shape. You can use a grinder or nail file to achieve this shape. Create coffin shaped nails. Coffin shaped nails are long with a flat tip and tapered edges, similar to a coffin. If you want this shape, then start by getting your nails to your desired length and then file down the tips of your nails until they are flat and even. Use a file or a grinder to get a straight flat edge at the end of each of your nails. Doing this will create a square shape, but you can taper the edges to turn the squares into coffins. Then, use a grinder or nail file to remove width along the sides of the acrylics that extend past your nail bed. Lightly file each side at a slight angle. Then, file away the sharp points at the corners of your nails. Soften square edges for sqround or squoval nails. Nails that are called sqround or squoval are simply square nails that have slightly rounded edges. It is up to you how much you want to round out the edges for this type of nail. To get sqround or squoval nails, start with square tipped nails and then begin to round out the corners of your nail tips. File towards the center of the end of your nail using a round motion. Do not file too close to the stress point of your nails. This is the area where the nail connects to your natural nail. This may increase the chances of breakage. Instead, just file along the free edge of the acrylics. You can use a grinder or a nail file to get this shape. Go for round or oval nails. If you like the rounded shape of squround or squoval nails, then you might even consider rounding out the tips a little more to create rounded or oval tips. Round tip nails have a shape that is similar to a half-circle, while oval nails have a tip that is similar to an egg. Round nails are the most conservative and they look best if you keep them somewhat short. For round nails, use a circular or arc-like filing motion to make your nail tips resemble a half-circle. Keep filing in this way until your nail tips are round and even. Oval nails are slightly more feminine, but still conservative. For oval nails, use a circular motion, but try to taper in the edges of your nails slightly as you do so. You can do this by applying a little more pressure on the outer edges of your nails as you file them. Use a nail file or a grinder to achieve a round or oval look. Give yourself almond-shaped nails. Almond-shaped nails are elegant and rounded with slight points at the tips. This is a great look if you have short or heavy fingers and you want to elongate them. It is also a really feminine look. To get almond-shaped nails, begin by marking the center point of the tips of your nails with a small dot of nail polish. This will make it easier to get even almond shaped nails. File towards the center point of your nails using a round motion. Do not file straight across. Try to move the file in a curved fashion. Repeat the same filing motion on both sides of your nails until you have achieved the almond-shape. You can use a nail file or grinder to do this. Try stiletto nails. Stiletto nails are daring, but they have become a popular look. These pointy, claw-like nails are sexy and ultra-feminine, but they are also not your everyday nail look. If you are considering trying out the stiletto nail shape, then start by marking the center points of each of your nails with a small dot of nail polish. Start filing towards the center point. File straight towards the center point of your nail to create claw-like tips. Do this on both sides of your nail until you have a pointy tip. Then, round out the tips slightly to eliminate the sharp edge. The tips should still be pointed, but not so sharp that you could scratch yourself or someone else with them. Check your lanula. The natural shape of your lunula can help you to determine what type of nails would look good on you. The lanula, or moon, is the white area of the nail that is just above your cuticle. Choosing a shape that mirrors the lanula or moon will help to ensure that it complements your nails. Look at your lanula to determine what nail shape would look best on you. For example, if you have rounded cuticles, then a round shape would look best. However, if your cuticles are somewhat square, then a square or squround shape would look best. Consider your fingers. Slim fingers will look good with almost any type of nail, but some nail shapes will complement wider fingers better while some shapes will make wider fingers appear even wider. Consider the length and width of your fingers to determine what type of nails might look best on you. For example, square nails might make wider fingers look even heavier. Squround, squoval, oval, or round nails will look good on just about anyone. Coffin or oval shaped nails can make your fingers look longer and slimmer. Look at pictures. Checking out photos of nail shapes that you like may also help you to decide on what shape is right for you. Browse pictures of different nail shapes and lengths to get an idea of what you like and don't like. Try creating the Pinterest board of nail shapes that you like. This can help you decide what shapes are the most appealing to you. Try it out. It is hard to know what will look good on you until you have tried it. If you are not sure what type of nail shape you want, then try starting with one that you can easily change into a different shape. For example, you could start with square shaped nails and then transition to round nails if you don't like the way the square shaped nails look. Avoid starting with a look that would be difficult to adjust to another shape. For example, it would be hard to change almond-shaped or stiletto nails into a different shape because of how much nail you will need to file away to get these shapes. 
Reduce the length first. Thin out the nail. Use a nail file for fine tuning the edges. File down the tips for square nails. Create coffin shaped nails. Soften square edges for sqround or squoval nails. Go for round or oval nails. Give yourself almond-shaped nails. Try stiletto nails. Check your lanula. Consider your fingers. Look at pictures. Try it out. 