Packing for any trip can be annoying if you don't know what and how much to pack. It's especially challenging if there is not a lot of space on your mode of transportation to carry multiple bags. However, there are some tricks to packing for a trips in compact spaces, such as a car or bus.
Remember that there is a weight limit (albeit high) on buses, just as on planes. Space is also a consideration to think of, as every passenger will need to stow their bag. Choose the bag that you pack according to available storage space and durability.
Invest in a suitcase with multiple compartments. This will not only give you additional spaces to pack items, but will also give you an element of organization to your packing process.
Pack your necessities first. This is underwear, solid-colored shirts and pants/shorts. Necessities would also include toiletries and any other items that you use on a daily basis. These items should be put into the suitcase first, with anything you know you might need in the next few hours going into your carry-on bag.
Prioritize your specialty clothing. These are the clothing items you don't necessarily "need," but you want to pack them anyway. If you run of out room, these are going to be the items to leave out first. This list would include extra pairs of shirts, pants or additional dresses. This includes multiple nightgowns or pajamas, extra pairs of shoes and your delicate material clothing. Pack them in order of importance so if you try to close your bag and it won't zip shut, the items you need to take out first are right on top.
Pack toiletries in a sealable bag or container in case something leaks or oozes out; the last thing you want is for your toothpaste or shampoo to end up all over your clothes. Another item to include in this section of your suitcase is your most sturdy, comfortable pair of shoes, the ones you wear with most of the clothing you packed.
Pack a small carry-on bag. Buses are fairly roomy and usually have overhead compartments that can accommodate a small overnight bag. Use this as your fallback for smaller items that may not fit in your suitcase as well as anything you think you might need during the actual bus ride. Don't jam pack it full of items or it might not fit into the compartment and you might be forced to stow it under the bus, defeating the entire purpose of packing a carry-on bag.