Use the depth of field.
This is what I do.
1 set manual focus and then set the minor focal lenegth (18,..etc)
2 If you have a tripod use it.
3 Set AV.
4 Use the bigest F number (22,20... etc,this will cause a very slow speed that is way you need the tripod)
5 Get close to the subjet, it does not matter if it gets blurry, make some shots and the review them. If they are too blurry you may need to get a steep back form the subjet, if it is sharp you may still have some distance to get a little close to the subjet.
The depth of field may give you some room to get colse to the subjet and still get a good photo.
The only problem is that you will have a very sharp background.