Iron Pipe valve wants to point down

I'm a novice installing a pedestal sink in my bathroom. I've replaced the valves on the iron threaded pipes coming out of the wall. The cold water pipe has developed a slow leak. When I was tightening it seemed to want to point down instead of up. I was worried that tightening it an extra half-turn would "overtighten" it and so I re-did the joint stopping a half-turn back. (looser). It was fine at first but has now developed a leak. I used joint compound on the joint. I would like to use the solid chrome copper pipes for connection to the faucet so it needs to point up. My question is, would it be better to tighten it on around another turn or re-do the joint with pipe tape or the like? Thanks in advance for the help.

A 1/2-turn shouldn't be a problem. Depending on the quality and condition of the threads, it wouldn't hurt to use both some tape then pipe dope.

Both the stub out and the valve are new, so the threads are in pretty good shape I think.

How worried should I be about "overtightening"? I have a feeling my tight might still be on the loose side, but there are a lot of warnings out there about "overtightening".

As long as you don't have a wrench longer than say 10-12", I don't think the average person could overtighten one without working at it. They should handle a couple of turns after finger tight at least.

Many of the things these days are not made here (here doesn't necessarily mean better, but often does), and the quality can often be spotty.

valve

It depends on why it stopped. If it was just because it was already tight then you should be able to go an additional half turn. BUT, it if is because the pipe is bottoming in the valve's thread, then trying to tight it will either damage the end of the pipe or crack the valve.