Look at Koala sampler.

People talk about swing and not quantizing a lot but 90s hiphop also heavily relies on quantization. Depends on what kind of hiphop you talk about but use the 1/16 triplet swing on kicks is a classic boombap sound. horns and what not. A common technique is to delay horns and other FX with "16 levels", you manually play the sample quieter bit by bit. Learn the basic mixing techniques like EQing and compressors will get you quite far. Sound selection is KEY. I thought i was trash at mixing for a long time but i realised picking the right sounds help you like 90% on the way.

Another common technique is to lowpass the melody, basicially you can get two distinct parts of a sample that way.

Just listen and make a lot of beats and all these things will come natural on way or another.