I am a bassist that is now learing guitar and I am getting petty fast but I have one issue with picking I can. Not pick upwards and when I do it sounds like crap any help please
practise. picking upwards and downwards is one of the most basic yet vital things. its called alternate picking and its the most important and most used type of picking. you need to practise your technique as bass playing has given you bad guitar habits.
If you can't alternate pick, do not focus on "getting pretty fast" for the time being. Focus on getting accurate and articulate, and then the speed can come later.

See the techniques sticky for some good alternate picking exercises. Play them slowly with a metronome and gradually increase the speed when you can play each one consistently and accurately.