Run SDO_TUNE.ESTIMATE_TILING_LEVEL() to get an initial tiling level estimate on your data - if possible try and use tool to visualize tiles
Use SDO_GEOM.VALIDATE_GEOMETRY() to ensure geometry correctness - if not correct may get unexpected results during index creation and SDO_GEOM.REALTE() functions
Memory - more is better
DB_BLOCKSIZE - set to at least 4K (2K is too small)
Rollback Segments - make sure have enugh space to create spatial index and may may need large one to handle initial load
Put data, indexes, and rollback segments in separate tablespaces
Make sure tables with spatial data has it's initial, next, and pctincrease values set correctly
Set initial extent for the SDO_GEOM_METADATA table (or <layername>_SDODIM tables for the relational model) very small so as not to waste space because these tables only have very few rows
Make sure SORT_AREA_SIZE paramter is large enough so sorting doesn't occur on disk since the RELATE() secondary filter uses a DISTINCT and ORDER BY clauses which uses it
LOG_CHECKPOINT_INTERVAL - make it large enough so that database checkpoints only occur at log switches, i.e. if DB_BLOCK_SIZE = 2048 (2K) and online redo log files of the database instance are 512K then the blocks/redo log file = (512000/2048) = 250 so make the LOG_CHECKPOINT_INTERVAL greater than 250
LOG_BUFFER - increase in increments of 5% so that more redo log changes are held in memory (SGA) so that they are less frequently written to disk
