I like to stay at a 45-90 degree angle from the SRM, that is, right of the storm direction. Here's an example of what I mean:
SRM northeast, I want to be east or southeast
SRM east, I want to be southeast or south
SRM southeast, I want to be south or southwest
The preferred area for me is about 45 degrees starboard of the updraft, as this maximizes the tornado's potential to pass very close to you (for photo/video ops) without necessarily putting you in the path. I stretch this preferred area to as far out as 90 degrees starboard of the updraft to account for any right-turning cells, which many discrete supercells become. This way you've got a cushion should the storm suddenly shift, allowing for both good viewing and _relative_safety.
The main obstacle I try to avoid is hail. Unless you're into it, giant hail is nothing but a hinderance and a headache (sometimes literally). Approaching a storm from the front (or head-on) is not only hazardous but a very bad angle for photogenic tornadoes. Even when you gain experience and get decent at punching cores safely, there's still the issue of visibility. I only approach a storm through the core if I've got no other immediate option; I won't leave a storm and go out of my way to stay safe......I'll take whatever quick solution seems the wisest. Granted, sometimes you find yourself in positions where there is no way to safely view the storm's updraft, and one must give in to the storm and let it go.....there will always be others.
As far as photo/video ops, direction of approach greatly influences this. Depending on your taste, you can opt for the classic, high-contrast backlit tornado (the tornado between the sun and you) or go for the equally-enchanting frontlit tube (you between the sun and the tornado). For backlit shots you'll want to be generally east or southeast of the updraft; for front lit tornadoes you'll want a more southwesterly or westerly approach. This is actually the safer method, because it puts you behind the updraft and away from most new mesocyclones that will develop in a cyclic storm...they tend to develop east of the older, occluding mesocyclones. However, as with all things supercell, there are exceptions. Sometimes new mesos can develop on the western flank of an occluding meso. But visual clues that got you there in the first place will give you a heads up that this is happening, so long as you're paying attention to things other than the meso-in-progress. The important thing is, always think ahead of the storm, always anticipate something new, something closer.
The one drawback to a westerly approach i.e., following behind updrafts, is sometimes the RFD will smack you around a bit. Just make sure you're nowhere within "reach" of power poles or other possible harmful debris and it's nothing more than some fun high wind that will provide a thrill in itself. Hopefully some of this will help you.