Bugs .. lay a fleece type blanket over the front of the car and soak it and let it sit on there to rehydrate the bugs. Biggest key .. wash them off often .. the longer they are on the harder they are to remove and some are acidic and will etch the clear.
Tar ... Naptha ... hardware store paint solvent for oil based house paint . Saturate a cloth and wet the tarred area and keep it wetted .. letting the solvent break the tar down. Don't go rubbing on it to do it .. a lot of tar can contain sand. I'm not a fan of the canned solutions. Also watch out if they contain Xylene .. not clear friendly.
Sap ... Rubbing Alcohol , and in some cases terpintine, depending on the sap/pitch.. same as above let it dwell and do the job. Also don't let the sap sit on the clear some will permenently stain it.