Hi Saucy and Welcome to Chordie!
Well.... If you have watched "Idol" the thing you always hear from the Judges is "Make it your own". Just because you are doing covers, doesn't mean that you HAVE to, or even want to, necessarily do the tune EXACTLY like the original. If it is a tune you like, use a bit of that freedom (artistic freedom) to change things up a little.
If you are having trouble with timing, use a metronome to give you a steady beat to follow with your strumming, a toe tap will do if you can keep it even. Play along with a recording of the original music to learn the chord changes as they relate to the lyrics and if you use something like Audacity, you can speed up or slow down the tempo without changing pitch of your playback and record your progress at the same time. Another thing to be aware of is that most of the music out there that is tabbed out or even scored in Chopro, is someone else's idea of what the chords are and may be transposed to suit their voice or preference.... may not even be close to the key of the original recording. If your version sounds way off to what you are playing with... grab that capo and move it around to see where it sounds best, then hit the transpose button to move it up or down to suit you.
Above all (here it comes) Practice practice practice!
Keep your chin up and hang in there.... it just gets better and better. Naturally, hang around here awhile and you will meet a whole bunch of friendly helpful people to get to know. Everybody's been where you are and understand where you are coming from.
Again Welcome! And Take Care;
Doug
"what is this quintessence of dust?" - Shakespeare