Here is a simple seven eight time exercise. Tap your foot to the beats so that the downbeat of the sequence is on "one" again on "two." (You should be now at the fourth eighthnote).

Now the next three eighth notes get one full beat (Your foot will progress slower in its tap than the first two).

So if this confuses you, simply count off the notes in seven's, and tap in these groups- [1-2][3-4][5-6-7][1-2][3-4][5-6-7]...etc.

Simply repeat this, and the chord changes should help if you get lost.

It sounds awkward, but some famous songs use this method a lot (i.e. Pink Floyd "Money" and Zeppelin's "The Ocean")