every lucid dream i've ever had i've been able to fly effortlessly. when i was around 9 or 10 i had my first lucid dream before i even heard of them, and as soon as i realized i was dreaming i flew really high up and explored until it faded away. and the second time i just flew at a high speed and plowed through buildings and houses.
but the only advice i can give you is just do it. don't even think about it, and fly. sorry but this is the best i can do. maybe you're just thinking about flying too much instead of just doing it. i don't know, maybe some can and some can't, and it may be different for you, but i never thought twice before i flew. it was never like "okay i'm going to try to fly" because "trying" implies that you might fail.

i hope this helps, and best of luck!