Applique is something many people find challenging. Learning how to make smooth edges and small stitches takes time but everyone can learn tricks to improve their skills more quickly. Investing in quality tools to help will you progress also.
If you want to do needle-turn hand applique you would benefit by taking a class where the instructor knows the ins and outs. It is a technique I like for small pieces with curvy details but don't have much opportunity to practise.
If you use freezer paper hand applique, then the Glue Pen might be a time saver and the skill booster you need. With this glue pen you can apply a fine line of glue to the seam allowance on the edge of the freezer paper. The seam allowance sticks to the paper until the glue is washed out. The glue looks blue when you apply it but dries clear. Whenever I used a glue stick I ended up with sticky fingers and the applique pieces glued to lots of body parts and sewing tools. With the glue pen, I can apply a thin line and keep everything non-sticky! The refills make it reusable and saves the cost of a pen every time.
Sometimes a little tool makes all the difference.