If sandpaper wasn't working sufficiently, and there is still a gloss to the surface of your tub, then you'll need to use an acid to etch it. Check your local hardware store or home improvement store for hydrofluoric or muriatic acid'. You'll want to be careful with this, follow all directions and be sure to ventilate the room.
You may have a beautiful old acrylic bath, one that you have treasured for years, and that you thoroughly enjoy. Now if it gets a scratch, it will be the same as if your car got a scratch. It is an obvious flaw that will eat away at top reglazing your patience with every glance you take. So, just like a car, you can apply car polish and gently apply it to the surface using a soft cloth.
One thing that you might have to do after owning and using one for a few years is to refinish it. This is an easy process that requires you to use specific tools and products. This should only be done when the pain on the outside or inside of the reglazing tub is chipped and coming off.
The next step is to cover the area where tub refinishing will not be applied. Those areas have to be covered with paper tape. Exercise caution when you are covering those areas with tape. Ensuring a good seal is of cardinal importance. After you have sealed up the rest of the area apply base coat to the tub. During this process ventilation is of utmost importance and should be ensured. Putting on your respirators is also a good idea if you have one. Go through the directions of the manufacturers and mix the primer's component accordingly. Spray it on the tub with the help of a spray gun or a similar device.
If you can afford something a little better then maybe you can get the solid surface countertop. They are more expensive than the laminates but these counters can be restored if you do get nicks and cuts. The most expensive and most durable countertops are quartz bath tub restoration and granite surfaces.
Start with the feet of the tub. Each foot is designed to fit in only one spot on the tub, so make sure you put them in their correct places. You may want to get a friend to help you with this. Install both feet on the plumbing end of the tub first, and then the feet on the opposite end.
You need to be cautious when you hire anyone to help you with your home, refinishing your bathtub included. A good bathtub refinishing job can be done from start to finish in a couple days and the look should last for years.