Any good tips on applying silicone properly?

I was doing the gap round the bath and ran masking tape round the tiles and
round the bath in order to create a nice sharp line. But the actual silicone
itself ended up drying kind of lumpy. I ran my wet finger over it after I
had applied it and it looked really smooth but didn't dry out that way. I
know screwfix sell a tool to smooth it, but would that make much difference?

Also what is the best stuff for removing silicone? I bought Silicone eater
or something similar from B&Q and left it overnight. It hardly took any of
it away. Ideally I would like to remove it all and reapply it again.
Thanks

Steven.