Learning a chart? Learn it backwards, ie the last 16 bars first, then the previous 16 etc.. that way, you're always moving towards music you've already scoped and learnt, rather than towards music you're still unsure of. By the time you're learning the first 16 bars, you already know the rest if the chart..
That is a very cool way of doing things I kind of lurn the main riff or the bit that gets me going first then the bit after then the bit before im more of a lurn it in patterns then put pattern A with B then C or what ever order they come lol
If it is a chord only chart, you should practise playing arpeggios on each chord. This can help you get good ideas for bass-lines. If it is a notated part for bass, you should play the written music until you have a good idea of the groove, then you can began adding some of your own personality to it. If you are in a room where everybody is reading their part you should play the part exactly as written. This is probably what the people who are paying you want. This is especially important in musical theatre or big-band numbers where chaos would ensue if everybody is jamming. Learning backwards is a good way to memorize charts but committing sections to memory is the key.