I use a very narrow V tool for most of my cutting,,well all of my cutting. It's 70* included angle. It works for making lines or if you want to flare the line to widen I just roll the tool. But the narrow point doesn't get you in trouble as Jerry has described in his post by cutting an uneven width that is easily seen as you cut an uneven depth. The latter you try not to do of course!.
Using the same tool for nick&dot,,just roll it over & and pull it up/out in an even cadence as you go along. No need to leave the surface of the piece. The burr should pop right off as you work along. Once in a while one will hang in there but you can go back and cut it off.
If the V sharpened tool still doesn't feel comfortable to you in cutting the nicks & dots and similar little triangle type decorative cut borders, try using a simple flat graver.
It has to be the simplest point to make up and sharpen. Keep it small, not much larger accross the face than the cut you are doing. Make sure the sides are truely perpendicular to the face so it doesn't form a wedge type action went entering the metal.
Sharpen with a steep face angle so you can see well what you are doing. Put a very slight heel on it so it doesn't dig in and stick there.
Think of it as 1/2 of a V shaped point but w/o all the hassle of the shaping and sharpening of the V.
The flat gravers cutting face is just about perpendicular to the surface you are cutting when doing the triangle cuts. Tip the tool up on one of the edges and cut into the surface at that angle to form the triangle cut.
A nice clean easily seen cut. Either come back to the end of the cut to complete the diamond shape,,or at the end of the original cut start to lift/roll the tool back out as you continue to hammer and complete the diamond that way.
You have one cutting edge but two points to stand the tool up on to. So you can cut from either side of a border or line. Try both, one will generally feel more comfortable than the other to you,,ie rolling you wrist back towards you or away from you as you hammer.
You can cut a lot with just a flat graver. Lines, flared lines, borders like the above, ect. It's really nothing more than 1/2 a V shaped tool as I said. But it is so much more easy to make, sharpen and keep sharp. Especially for a beginner engraver or someone who just wants to occasionally cut a few lines and not make a career of being a professional tool sharpener.