Pretty vague. Are there particular challenges you are caught up with how to do, given your time constraints or..?
But I mean, basically just keep working toward completing all your synth stuff and just be efficient with your time -- always be doing something challenge-related while you are online instead of idling in your hideout, for example.
Just take a good look at the challenges and note which ones you'd probably need to be cognizant of. For example the one to identify synth mods on items. I dismissed this one at first but now I pick up all items and ID them even if I don't want to synthesize them.