In the last 6 to 8 months I've seen a big issue with traffic patterns at both controlled and uncontrolled airports. I offer two suggestions. One, Listen to ATC and Two, follow the regulations.
If the controllers instructions don't make sense, ask for clairifaction. ATC will generally have you enter the pattern via the shortest route, if they don't they usually will offer an explanation ("for ILS traffic enter the mid-field left downwind"). If something doesn't make sense, either you or ATC doesn't have the complete picture. Make sure both of you are on the same page!
Standard traffic patterns are essential for your and everyone elses safety, please use them. All traffic patterns are to the left unless otherwise depicted! At uncontrolled fields remember to make position reports but don't expect others to do the same. Some aircraft may not have radios.
Lastly, traffic pattern altitudes can be found in the AFD. FYI, for small aircraft, most patterns are flown at 1000 ft AGL (but not all airports are that way).