There are several shapes of glass tips for pre-rolls, each with its own unique features and benefits. Some of the most common shapes include:

1. Straight: This is a simple, straight cylinder shape that provides a smooth draw.
2. Cone: This shape is tapered, with a wider opening at one end and a narrower opening at the other. It can help prevent the pre-roll from getting clogged.
3. Flat: This shape is flattened on one side and rounded on the other, providing a comfortable grip and preventing the pre-roll from rolling away.
4. Flared: This shape is wider at the mouthpiece end and narrower at the other end, providing a more comfortable grip and reducing the likelihood of the pre-roll slipping out of your fingers.
5. Pinched: This shape is pinched in the middle, providing a more secure grip and preventing the pre-roll from slipping out of your fingers.
6. Hourglass: This shape is wider in the middle and tapered at both ends, providing a more comfortable grip and preventing the pre-roll from rolling away.
7. Spoon: This shape is similar to a spoon, with a curved end that fits comfortably in your mouth.
8. Bubble: This shape has a small bubble in the middle, providing a more comfortable grip and preventing the pre-roll from rolling away.
9. Twisted: This shape has a twisted design, providing a unique look and feel.
10. Custom: Some glass tips can be custom-made to fit your individual preferences and needs.

When choosing the right shape for you, consider the following 10 advices:

1. Consider the size of your pre-roll. Make sure the glass tip is appropriate for the size of your pre-roll.
2. Think about your personal preferences. Do you prefer a wider or narrower tip? Do you prefer a straight or tapered shape?
3. Consider the material of the tip. Glass tips are popular, but some people prefer tips made from other materials, such as wood or silicone.
4. Think about the style of the tip. Do you prefer a simple, elegant design, or a more unique and creative shape?
5. Consider the thickness of the glass. Thicker glass can be more durable and resistant to breaking.
6. Think about the length of the tip. A longer tip can provide a cooler smoke, but a shorter tip can be more portable.
7. Consider the grip of the tip. Some shapes are easier to hold than others, depending on your personal preference.
8. Think about the shape of your mouth. Some shapes may be more comfortable for your mouth than others.
9. Consider the price of the tip. Glass tips can range in price, so think about how much you’re willing to spend.
10. Read reviews and get recommendations from others to find the best glass tip for you.