Here's a great way to improve your pitching with vocals. This is a simple exercise that ascends through four chromatic notes - C/C#/D/D#. Chromatic notes are notes that are sung or played in exact steps - play each note as you ascend or descend, you don't skip note like you do in true scales. The actual key (such as it is) is not important, these notes are for demonstration purposes. Start with any note you like and apply this chromatic exercise. Simply sing each note but pay close attention to your pitching. Try starting on different notes to expand your technique and vocal range.
Often scales or arpeggios are used for vocal warm-ups. If you're not already doing it add some chromatic exercises like this one to your vocal warm up routines. They really help you hone in on accurate pitching.
You do not have to restrict yourself to four notes either. Try five, six, seven or more note runs. Vary how many notes you use. Descend through your patterns also.
Last up, you'll notice that the notes here are staccato. That is you sing each note as a short, tight note. Don't let your notes ring out like you usually would, tighten them up into tight vocal stabs. But this doesn't mean to tense up, stress your neck muscles, blast your vocal chords and so on. Remain relaxed throughout the exercise.