My guess is (correct me if I am wrong) that you go at these songs at "full speed ahead." If so, my suggestion would be to isolate the parts you are constantly messing up. Narrow it down to about thirty to forty five seconds. Then at the beginning and end of each practice session, spend about five minutes
SLOWLY repeating the problem section. Play very slowly and deliberately (almost exaggerated to start). Then
gradually up the tempo a little and repeat. If you falter at a certain tempo, return to the previous one, then try again to increase it. Do this with each problematic section. When you think you have a section down,
then try playing along to the song at it's normal tempo.
Dont spend more than five minutes at one go on a particular section. Take a break and come back to it. Little and often is best. Above all, dont become frustrated. With a little time and patience, I'm sure you will nail those problem bits.
Hope this helps.