Hi,
I am not a pro, but I can share what I’m doing.
First, I use Traktor so I can see the phrases.
It is really helpful.
AFAIK, techno, tech-house are usually 32 beats phrases (8 bars).
To your question, yes, usually a phrase ends or starts with a drum fill, crash or similar.
So even if you’re not really sure, listen to the change and start counting. You’ll see that after 8 bars you will hear another change.
I use loops of 8 bars a lot. I start the loop in the 2nd deck when the phrase starts in the 1st deck (even w/o volume at all).
Then I can start mixing, being sure I’m in the phrase.
I came upon a good tutorial about it.
http://djtechtools.com/2014/11/16/how-to-dj-101-why-you-must-understand-phrasing/
It’s good if you use Traktor, which I understand you don’t.
Hope it helped a bit.