What do you look at when you shop online? Probably something that feels right, where you can find what you want to buy and that you can trust.
The less options you provide the easier it is for your customer to decide what they'll buy.
Use a header image and background image that is not too compressed or too small. It will take the customer a bit more time to download, although this is usually not a problem. Great images add to the event experience and trustworthiness.
You can add a ton of extra questions, but it will probably not benefit you. Usually this is driven from a marketing perspective. You want to know who the person is and what you might be able to sell to them in the future. But it is better to focus on closing the deal, making the transaction happen and creating a great event that will leave a positive impression, instead of filling your marketing database.
One of the first items a customer looks for are key trust indicators. When they can't find contact details, there is a good chance they won't find you a reputable party and leave.
You can add categories and move tickets around.
Credit Card payments are a bit more expensive that the other local payment options, but they'll increase your conversion dramatically.
Many companies need an invoice before they can pay. It takes a bit more time on your side to process the invoices, but it's worth it.