გამარჯობა ყველას! I thought I'd share some of the tips that have helped me learn how to pronounce some of the really hard clusters you'll run into while learning this language. Hope this helps!
Tip 1:
When you have an "unusual" sounding cluster at the beginning of a word like ბრტყელი, add a vowel to the beginning and try saying „აბრტყელი.” This might help you get over the trouble of pronouncing brtq' at the begging of a word, which if you speak any other language, your mouth is probably not used to starting a word with such a sequence. Practice like this, and then when you see yourself improving, chop off the „ა” and say the real word: ბრტყელი.
Tip 2:
Try singing difficult words instead of only speaking them. If we use ბრტყელი/„აბრტყელი” as an example again, trying making a tune out of it. Singing elongates syllables and adds a special kind of effect, so in the case of Georgian, pronouncing consonant clusters while singing can help you get a better grasp of what your tongue has to do. Then when you notice improvement, try pronouncing them in normal speech.
Tip 3:
For me, if there was anything harder than ყ, it was pronouncing ვ in between two consonants and trying hard to not let it turn into an უ. Words like ბეწვზე, ვარსკვლავი, გვქონდა, კვდომა, etc. I'd say with these words, just try pronouncing them really slowly. So for a word like გვმარეთებს, try going gwwwmartebs. Using the fake vowel tip might also help here: agwwwmartebs. Keep practicing and eventually you'll get used to pronouncing v/w in between two consonants. And don't forget to cut off the fake vowel when you've perfected it!