for the best results, dont build the entire model and then try and paint it. Know what the model is going to look like before you start, and paint bits as you go. That way the finish will be much sharper and more detailed.
Dont use glue squeezed straight from the tube onto the model. Use a match stick or bruch head glue applicator. Applying just enough glue means the finish will be neater and not so messy.