Using many different rhythm figures often makes picking confusing. Eighth notes are easy because the picking alternates. For triplets and sixteenths however, there are often problems. When playing eighth note triplets it is a good idea to practice them in three ways.
1.All down strokes.
2.Alternating.
3.Down - up - down.
When picking sixteenth notes the general principal is to play a downstroke on any beat or any "and", but to use an upstroke on any "e" or "a". Here are some examples to practice.