Learn to push out and layer your pranna in various levels of tension around the flame you are trying to manipulate, there are four main forms of pranna that i recommend you become accustomed with for the most effective results, these forms of pranna should be drawn in and compressed slowly but surely through your whole physical body.
The types of pranna are as follows- red pranna - draw it from the core of the earth, this pranna has the greatest effect compared to others when it comes to elemental wielding and manipulation. Gold pranna - this is drawn from your on body and being, it can either be drawn from your lower dan tien or your kundalani. Blue pranna - this is drawn from distant light such as stars, and lastly white pranna, drawn from the moon.
Each different type of pranna allows you to get a grip on fire on a different level, thus combining them into a layered whole is one of the best ways to get visible results.
Also learn to work with mental and physical tension.