I'm on an economy drive, so I currently do my brows and lashes myself.
I use the pro stuff I bought from Amazon. That said, I have had them done at a salon hundreds of times, and have paid attention to how they do it.
My method for lashes is to do one set at a time i.e. Bottom right, then bottom left etc. for me, the thing which works the best is to use one of those small in between tooth brushes. I tried a brush, a mascara brush, a cotton brush, but the mini brushes gave me the best finish.
I use a wax based balm under my eyes and round my brows to prevent smudging. With brows, I've also tried loads of techniques, and have eventually settled on a toothbrush. I use the balm, then brush the brows up using a dry brush, before brushing though with the dye. I use a dark brown for my brows (which are naturally dark anyway - but now have loads of white hairs) and black for my lashes. My brows are fairly thick, so I just tidy up round the edges with tweezers every week.
I do a patch test every few month, just in case, and take my time in doing them. It usually takes me around 45 minutes. But I work slowly and carefully. I would recommend a salon if you want them doing quickly, or for a first time.