The place of articulation of GA /k,g/ is very similar to that of Dutch /k/ and marginal /g/. Adjacent front vowels cause varying degrees of fronting depending on the frontness of the vowel. GA /k,g/-fronting is stronger before or after /iː/ than /ɛ/ and absent with open or back vowels like /ɑː/ or /oʊ/. In Limburg varieties of Dutch, velar fronting is generally stronger before opener front vowels: such learners should avoid fronting /kg/ in words like beg, back.
If we do not have marginal /g/, concentrate on pronouncing a weakly articulated voiced stop in voicing contexts, as in again, no good, and a weakly articulated, slightly devoiced stop after voicelessness, as in go, great. Before voicelessness, as in rug, again make a gentle contact, with a weak but audible release. Here are some examples to practice some of the main /k,g/ allophones:
[kʰ] kiss, car, viscount, encode, concourse, account, encore, kazoo, napkin
[k] skin, school, reckon, discuss, bucket, unscathed, knuckle, escort, anchor
[k͜ʔ] stick, sock, six, rockband, blackmail
[g̥] big, hug, disguise, lifeguard, magpie