I just watched a you tube clip where a guy is adding eq and compression to the vocal track, and then adds a double track and adds reverb and then another double to add chorus. It sounds great, so now i am confused about, what is the best way. I usually adds everything to one single vocal track. What do you people do when mixing vocals, add everything to that one track or making doubles of the same track and add reverb, delay and chorus?
For recordings I make at my studio I almost never copy a vocal track to add differing effects. What I do is to have the talent record two good separate takes. Then I will use those two tracks adding effects to each as I see fit. This sounds much better to me. I like the slight variations in the two different takes blended together. But, singing two similar tracks is tough. Even for good talent. So every so often I do have to cut the 2nd vocal track as necessary to line up with the first if it is too far off (time). But, I do like the variations of the two separate takes blended together so it has to be pretty far off for me to cut it to line up.
Regards 
“Best” is what sounds the best to you… It’s all subjective and there’s multiple ways to achieve what you’re asking. In my case, I sing the part a second (or third) time. I’d point the outputs of those vocal takes to a Group channel where I’d use EQ/dynamic control if needed. I’d use Revoice Pro to tighten the phrasing between the “main” vocal and the “double” vocal. Then, set up a FX track for each FX I want - Reverb, Chorus, Delay. I’d then use Sends from the vocal group channel to the separate FX tracks applying the amount of send to taste… I usually eq the FX tracks too with a boost/cut on the low & highs to highlight that particular effect a tad more…
Thanks, but that´s not exactly, what I am talking about. I also create harmonies with several different recordings. What the guy did was making a double of the exact same vocal recording, not to make harmonies but to “boost” volume I assume and to be more in control of the effects added to the clone. I want to know, if this is a better way of mixing vocals? 
see the clip here, where he explains it. https://www.youtube.com/watch?v=sPRm0uikJMs
I have to bug out so I’ll check out the vid later but, I was not talking about doubling harmony tracks. I am talking about recording two tracks of the same melody and using those two tracks instead of copying the original track. This is not for harmony purposes.
Later… 
Regards
I have just created a mix using the same method as in the you tube clip. I am not sure of, if this is a better method. I can hear, that volume is boosted by making the clones… I have tried similar method sending to FX channels, and it seems to be same result. I guess, that it is a matter of choice…
After checking out the vid, I hear the volume increase that you noticed. These differing methods are definitely a matter of choice of what you are trying to achieve soundwise. Also, workflow preference comes into play too.
Glad you shared the video and asked the question. I hope a few others chime in with their opinion too. 
Regards.
I do it all the time, both on vocals and bass
It’s the easy way of doing parallel processing.
On lead vocals I almost always duplicate the track and use hi and low cut so only the mids remain, then add some distortion, it then sounds like a bad telephone connection. Fade that in till you hear the vocal fattening up. I usually use that ( bad phone signal) to send to a delay and reverb. If done right it can really bring the vocals to the front, when you have found the sweet spot, just link the faders or use a VCA to control the level.
I haven’t seen the video but it sounds like using parallel compression which can boost the perceived volume of a track. One way is to duplicate the vocal track for instance and apply compression to the duplicated version. I would have a medium threshold to start with and a gain reduction of about 6 db, then play with the volume against the original track. You can do this also by creating a group channel (insert a compressor) and send the vocal track to it via a send slot send, using the downward arrow and selecting the group channel. This way you can add a number of tracks to the same compression channel. It is amazing the extra perceived volume.
Oops! Great minds think alike peakae.
so if i understand you correctly, you do not do anything to the first lead besides compression, deesser and so on? Its the dublicate you send to delay and reverb?
Yes usually, I might have been inspired by Dave Pensado’s “into the layer” videos he does that a lot.
Inspire that is.