If you have previous criminal convictions, make sure and tell your attorney about them.
I’ve had several clients who have tried to conceal their previous convictions and pleas from me. You might think that makes you more believable in the eyes of your attorney, but when your attorney is trying to negotiate your case with the prosecutor, it does not help when the prosecutor reveals that you’ve had a lot of experience in the legal system already. It hurts your credibility as a defendant and some of those previous convictions may be used against you in this case.
Do yourself a favor, be honest to your attorney.